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91.
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93.
Seagrass research in China is still in its infancy. Even though there has been progress recently, there is still a great deal
of research needed to gain a better understanding of seagrass. In this article we review and discuss the advances in seagrass
research in China from two aspects: (1) seagrass species and their distribution; (2) seagrass research in China, including
studies on their taxonomy, ecology, photosynthesis, applications in aquaculture, salt-tolerance mechanisms and other research
topics. A total of 18 seagrass species belonging to 8 genera are distributed in nine provinces and regions in China (including
Hong Kong and Taiwan), as well as the Xisha and Nansha Archipelagos. They can be divided into two groups: a North China Group
and a South China Group. Based on the seagrass distribution, the Chinese mainland coast can be divided into three sections:
North China Seagrass Coast, Middle China Seagrass Coast, and South China Seagrass Coast. Ecological studies include research
on seagrass communities, nutrient cycling in seagrass ecosystems, genetic diversity, pollution ecology and research in the
key regions of Shandong, Guangdong, Guangxi, and Hainan. Seagrass species and their locations, community structure, ecological
evaluation, epiphytes, ecological functions and threats in the key regions are also summarized. Other studies have focused
on remote sensing of seagrass, threatened seagrass species of China, and pollen morphology of Halophila ovalis. 相似文献
94.
95.
The cracked chevron-notched Brazilian disc (CCNBD) was proposed by the International Society for Rock Mechanics (ISRM) to test the mode I (opening mode) fracture toughness of rock. The test method has been vigorously discussed and debated, despite being the subject of intensive research for decades. The minimum (critical) dimensionless stress intensity factors affiliated with the formula for calculating the fracture toughness using CCNBD specimens with different geometric parameters remain elusive and complex. The matter cannot be resolved by simply replacing the diameter in the original formula with the radius, as claimed by several authors. In this paper, the formula is fundamentally improved, as wide-ranging minimum dimensionless stress intensity factors pertaining to diversified CCNBD geometries are recalibrated by three-dimensional finite element analysis, and an expression with tabulated coefficients is obtained through curve-fitting the data obtained from the numerical calibration. The present results are shown to be more accurate than those in the literature. Furthermore, the importance of the reasonability of the results is highlighted; a comprehensive comparison of different values shows that the upper bounds of minimum stress intensity factors are violated by the above claim. The confusion resulting from the claim is, thus, clarified conclusively. 相似文献
96.
无人机遥感系统由于具有响应迅速、起降方便、可低空作业、分辨率高等优点,在自然灾害调查及应急救援中有广泛的应用。文章在台风"苏力"登陆后,利用无人机遥感系统及时获取台风登陆点附近25km~2范围的高分辨遥感影像,通过对遥感影像进行分析处理,提取研究区域典型风暴潮承灾体的灾害损失信息并对其进行统计分析,为风暴潮灾害损失评估提供数据支持;对无人机低空遥感系统在风暴潮灾害调查及灾害损失评估中的应用作初步探索。结果表明,无人机低空遥感系统在风暴潮灾害调查中的应用具有一定的可行性且取得一定成果,但受制约的方面也较多,今后还需结合风暴潮灾害特点作进一步的应用探索。 相似文献
97.
98.
D. J. Fan R. D. Neuser X. G. Sun Z. S. Yang Z. G. Guo S. K. Zhai 《Geo-Marine Letters》2008,28(1):7-14
Estuaries are elementary geochemical fronts where river water and seawater mix. Within this mixing zone, iron and other non-conservative
elements can undergo complex reactions to form new solid phases. In order to understand authigenic iron oxide formation in
the Yangtze River Estuary, two onsite water-mixing sets of experiments were conducted, one by mixing variable amounts of unfiltered
Yangtze River water with filtered East China Sea water of different salinity (set 1), the other by mixing variable amounts
of filtered Yangtze River water with filtered East China Sea water of different salinity (set 2). In set 2, the minerals newly
formed in the course of mixing were investigated by means of a scanning electron microscope fitted with an energy-dispersive
X-ray analytical system. It was found that ferrihydrite and lepidocrocite were formed in these mixing experiments, coexisting
in nearly equal amounts. These iron oxides appear as aggregated particles with a large grain-size range of several microns
to more than 100 μm. The electrolytic properties of seawater played an important role in the formation of these authigenic
iron oxides. Kaolinite and organic aggregates were also found in the experimentally mixed pre-filtered waters. Amounts of
newly formed suspended matter (set 2) were one to three orders of magnitude lower than those of total suspended matter (TSM)
(set 1). This implies that newly formed minerals represent only a very small proportion of TSM in the estuarine mixing zone
of the Yangtze River. 相似文献
99.
樊杰 《中国地理科学(英文版)》1994,4(1):43-54
ANANALYSISOFTHEPOLICY-MAKINGINREGULATINGTHEINDUSTRIALSTRUCTUREANDDISTRIBUTIONINTRADITIONALINDUSTRIALBASEINMIDDLELIAONINGPROVI... 相似文献
100.
We investigated seasonal variations in cyanobacterial biomass and the forms of its dominant population(M. aeruginosa) and their correlation with environmental factors in the water source area of Chaohu City,China from December 2011 to October 2012. The results show that species belonging to the phylum Cyanophyta occupied the maximum proportion of phytoplankton biomass,and that the dominant population in the water source area of Chaohu City was M. aeruginosa. The variation in cyanobacterial biomass from March to August 2012 was well fitted to the logistic growth model. The growth rate of cyanobacteria was the highest in June,and the biomass of cyanobacteria reached a maximum in August. From February to March 2012,the main form of M.aeruginosa was the single-cell form; M.aeruginosa colonies began to appear from April,and blooms appeared on the water surface in May. The maximum diameter of the colonies was recorded in July,and then gradually decreased from August. The diameter range of M. aeruginosa colonies was 18.37–237.77 μm,and most of the colonies were distributed in the range 20–200 μm,comprising 95.5% of the total number of samples. Temperature and photosynthetically active radiation may be the most important factors that influenced the annual variation in M. aeruginosa biomass and forms. The suitable temperature for cyanobacterial growth was in the range of 15–30°C. In natural water bodies,photosynthetically active radiation had a significant positive influence on the colonial diameter of M.aeruginosa(P0.01). 相似文献