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941.
分别利用近震波形反演求解震源机制解的gCAP方法和全波形反演方法反演了鲁甸MS6.5地震的震源机制解,并比较两种方法的优点与特性。结果发现,数据方位角的覆盖范围会影响解的稳定性,在使用gCAP方法时尤其需要注意;两种方法获取的震源机制解结果较为一致,走向为73°~77°,倾角为72°~85°,滑动角为157°~180°。 相似文献
942.
【目的】了解马氏珠母贝(Pinctada fucata martensii)肠道及其养殖水体可培养细菌的群落组成。【方法】采用2216E平板涂布法研究海区养殖马氏珠母贝肠道与养殖水体的可培养菌群种类及丰度。【结果与结论】马氏珠母贝肠道及其养殖水体的可培养细菌归属于2门(变形菌门和厚壁菌门)3纲7目10科23属56种。属水平上,肠道中以弧菌属(74.7%)和假交替单胞菌属(18.7%)为主;养殖水体中α-变形菌纲的FJ943236_g属(40.7%)丰度最大,弧菌属(16.7%)相对肠道丰度较低。样品共有菌属为弧菌属、假交替单胞菌属、发光杆菌属和芽孢杆菌属;肠道特有菌属为希瓦氏菌属和盐单胞菌属;养殖水体特有菌属主要为FJ943236_g、鲁杰氏菌属和Nautella。在种水平上,7个种为二者共有;马氏珠母贝肠道和养殖水体特异性菌种分别为18个和31个。虽然门水平上马氏珠母贝肠道中可培养细菌群落与其养殖水体中的细菌群落大致相似,但在属、种水平上二者差异明显。 相似文献
943.
随着城市管理和空间大数据、5G、人工智能等新型技术的深入结合,新型智慧城市相关的应用成为地理信息行业领域与社会重点关注的对象。本文主要介绍了智慧城市的背景与概念、理论与技术,阐述了数字城市、智慧城市及数字孪生城市三者的关系,总结了数字孪生城市现状及趋势,并探讨了元宇宙时代的智慧城市。智慧城市的萌芽期依靠空间信息技术、数据库技术、虚拟现实技术及计算机网络技术等构建数字城市,发展期在数字城市基础上融合人工智能技术、物联网技术、云技术及时空大数据技术等建设新型智慧城市,建设期结合新型智慧城市相关技术和实景三维技术等实现数字孪生。展望了跨时代的元宇宙智慧城市,或许会在数字孪生的基础上融合增强现实、扩展现实、脑机接口与体感设备等技术或设备,实现人类生活在两栖世界的美好憧憬。 相似文献
944.
China’s Qinghai-Tibetan Plateau (QTP) is an important area for bird conservation, with many endemic and Threatened species. Colonial burrowing mammals play an important role in structuring bird communities in arid grasslands around the world. On the QTP, the plateau pika Ocho tona curzoniae builds colonies which provide a dense source of resources for many bird species. However, pikas are regarded as a pest by local pastoralists, and they are the target of a population reduction campaign which could have a significant impact on the bird communities. We surveyed bird communities at Gansu Yanchiwan National Nature Reserve to investigate the differences in community structure between sites with pika colonies (on colony) and sites without them (off colony), and between pika colonies which had been poisoned and those which had not. Using non-metric multidimensional scaling (NMDS) combined with permutational multivariate analysis of variance (PERMANOVA) and Wilcoxon rank-sum tests, we found that there was no significant difference in bird community composition or abundance between the poisoned and untreated colonies. However, there was a very large and statistically significant difference in bird community structures between on- and off-colony sites. Only horned lark Eremophila alpestris was consistently observed at sites without pika colonies, while ten bird species were observed on colonies. Six species were significantly more abundant on colony than off. While we could not claim that the poisoning campaign at Yanchiwan is altering bird communities, the presence of pika colonies seems to be an indispensable resource for the resident birds. 相似文献
945.
946.
针对TV图像复原方法中产生的阶梯效应问题,结合传统的差值范数图像复原方法,提出一种四阶P-Laplace图像盲复原算法。该算法将四阶偏微分方程引入P-Laplace图像复原方法中,对图像的边缘和内部平滑区域做了分别处理以缓解TV复原方法中带来的阶梯效应,同时引入参数λ调节复原过程中的保真项,并对偏微分方程做单调灰度变化,进一步改善了图像复原效果,缓解了阶梯效应。实验结果证明,该算法对模糊图像有很好的复原效果,也适用于水下图像和雾天图像的图像复原。 相似文献
947.
??????????λ???????????μ????????????????????????÷?????????????0.5 m????????????0.2 m??????????????????????????????????????????????????÷???????????????????????2 h????????λ?? 相似文献
948.
Interannual variability and correlation of vegetation cover and precipitation in Eastern China 总被引:5,自引:1,他引:4
Dejuan Jiang Hua Zhang Yong Zhang Kun Wang 《Theoretical and Applied Climatology》2014,118(1-2):93-105
Based on the SPOT/VEGETATION Normalized Difference Vegetation Index (NDVI) data and daily precipitation data of 357 meteorological stations, the spatial and temporal variability of vegetation cover, measured by NDVI, and precipitation as well as their relationships are investigated in Eastern China, which is portioned into three subregions (regions I, II, and III), for the period 1998–2010. The results show that high NDVI values appear mainly in Northeastern China and in August while high precipitation (PRETOT) occurs in Southeastern China and in July (June for Southern China). Extreme precipitation days (RD95p) and amount (EPRETOT) coincide well with PRETOT. Extreme precipitation intensity (RINTEN) has a similar spatial variability to PRETOT but with a smaller seasonal variation than PRETOT. Growing season NDVI is positively correlated with PRETOT in 11.7 % of the study area (mostly in arid to subhumid regions of Northern China), where precipitation is a limiting factor for vegetation growth. In contrast, a negative correlation between growing season NDVI and PRETOT is found in 4.8 % of the study area, mostly in areas around the Yangtze River and deep Northeastern China. No significant correlations between these two variables are found for the other regions because vegetation response to precipitation is affected by other factors such as temperature, radiation, and human disturbance. On a monthly scale, there is a positive correlation between NDVI and PRETOT in May (for region II) and September (all subregions except region I). NDVI variations lag 1 month behind PRETOT in June (for region I) and October. Correlations between NDVI and RD95p, EPRETOT are similar to that with PRETOT, but the relationships between NDVI and RINTEN are relatively weaker than with PRETOT. This study provides the technical basis for agriculture development and ecological construction in Eastern China. 相似文献
949.
950.