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71.
左平怡 《湖南地质》1992,11(1):53-60
本文以水口山、宝山、锡矿山、洪水坪、湘潭锰矿等各矿区的实际资料为依据,从影响矿坑涌水量计算的诸因素中,提出了矿坑涌水量全年中出现次数最多的值作为涌水量的基准值的概念,并以此值大小把矿坑涌水量分为3大类7亚类;对涌水量的动态变化采用涌水量最大值与正常值之比作为不稳定系数来表达,并将其分为4类;据动静储量的比例系数值把矿坑水储量分为静型、静动型和动型3类,从而确定了涌水量计算的内容,对计算精度依照基准值分类各划分了四个等级和相对应的储量等级,同时确定了相应的误差值与评分标准。  相似文献   
72.
Iatroscan TLC-FID combines the separatory capabilities of thin-layer chromatography (TLC) (on silica coated chromarods) with the possibility of quantitation by flame ionization detection (FID). It can be used to separate lipid extracts into classes of compounds ranging from neutral to polar products. The rapidity with which this system provides lipid class profiles from small samples makes it particularly useful in oceanographic studies where routine analyses of large numbers of samples are required. Lipid classes were analysed in 4 marine bacterial strains grown on various substrates and 10 microalgae isolated from the marine environment and grown in batch cultures. Data on lipid composition of these microorganisms were obtained and compared to literature data. Results show that ratios between classes of compounds within the different groups of microorganisms were characteristic enough to constitute a good print of bacterial or phytoplankton sources in organic matter in sea water. In a preliminary study, phospholipid classes from a bacterial strain and a microalga were separated. Results show that the determination of ratios between phospholipid classes in organic matter could represent an improvement in the utilization of lipid classes as biomarkers.  相似文献   
73.
本文以笔者调查资料为基础,扼要阐明了三山岛产卵场的鱼类种类、水域生物学与地理学条件及形成该产卵场的机理,并根据当前渔业资源状况,提出了建立《资源保护区》的建议,以为黄渤海渔业资源的可持续利用奠定基础。  相似文献   
74.
Incorporation of 14C-depleted (old) dissolved organic carbon (DOC) on/into particulate organic carbon (POC) has been suggested as a possible mechanism to explain the low Δ14C-POC values observed in the deep ocean [Druffel, E.R.M., Williams, P.M., 1990. Identification of a deep marine source of particulate organic carbon using bomb 14C. Nature, 347, 172–174.]. A shipboard incubation experiment was performed in the Sargasso Sea to test this hypothesis. Finely ground dried plankton was incubated in seawater samples from the deep Sargasso Sea, both with and without a biological poison (HgCl2). Changes in parameters such as biochemical composition and carbon isotopic signatures of bulk POC and its organic compound classes were examined to study the roles of sorptive processes and biotic activity on POC character. Following a 13-day incubation, the relative abundance of the acid-insoluble organic fraction increased. Abundances of extractable lipids and total hydrolyzable amino acids decreased for both treatments, but by a greater extent in the non-poisoned treatment. The Δ14C values of POC recovered from the non-poisoned treatment were significantly lower than the value of the unaltered plankton material used for the incubation, indicating incorporation of 14C-depleted carbon, most likely DOC. The old carbon was present only in the lipid and acid-insoluble fractions. These results are consistent with previous findings of old carbon dominating the same organic fractions of sinking POC from the deep Northeast Pacific [Hwang, J., Druffel, E.R.M., 2003. Lipid-like material as the source of the uncharacterized organic carbon in the ocean? Science, 299, 881–884.]. However, the Δ14C values of POC recovered from the poisoned treatment did not change as much as those from the non-poisoned treatment suggesting that biological processes were involved in the incorporation of DOC on/into POC.  相似文献   
75.
Humlum, J., 1973: Den 4. Internationale Kartografkongres, Canada, 1972. Geografisk Tidsskrift 72, 68–70. København, September 30, 1973.

4th International Cartographic Association Conference. Canada 1972.  相似文献   
76.
Negative trends of measured pan evaporation are widely reported. Studies of the factors that underlie this reduction in pan evaporation have not reached a consensus about the controlling factors. Most studies employ statistical analysis (correlation analysis or stepwise regression) to identify the controlling climatic variables; in contrast, few studies have employed physical‐based theories. In addition, observations of pan evaporation and related climatic variables are reported to be influenced by anthropogenic activities. Consequently, the observed trends of climatic variables in a nature reserve would be useful for understanding regional climate change. The present study site is located in Ailaoshan National Nature Reserve, SW China, which is free of anthropogenic activity. In this study, we firstly applied the adjusted PenPan model to estimate the pan evaporation. Then, using this physical‐based model, we identified a positive trend in pan evaporation, with a much larger increase in the dry season than in the wet season. The model results indicate that the change in the aerodynamic component is larger than that in the radiative component. In contrast to the reduction in wind speed and sunshine hours that has been reported in previous studies at various sites, we found that wind speed and sunshine hours have increased in recent decades, thereby explaining the increase of the pan evaporation rate. Wind speed made the greatest contribution to the change in pan evaporation, followed by sunshine duration. This study indicates that the potential evaporation has increased at this site despite the widely reported reduction in measured pan evaporation. During the dry season, the availability of water for agriculture and agroforestry could be threatened. Copyright © 2012 John Wiley & Sons, Ltd.  相似文献   
77.
Coastal engineering works, especially the outer breakwaters of ports where environmental conditions are usually good, often constitute new habitats for marine littoral species. Their potential indirect contribution to the regeneration and conservation of protected species opens up a new perspective in protection of marine biodiversity. This is particularly true when these works harbour, as we show here, important reproductive populations of species that are threatened or even in danger of extinction. We provide integrated data on protected marine species in Southern Iberia established on different substrata (quarried dolomitic rocks, concrete cubic blocks, concrete tetrapods and vertical concrete walls) that are used in the construction of artificial levees that could potentially be Artificial Marine Micro‐Reserves (AMMRs). We also present the first evidence of the ‘reserve effect’ in potential AMMRs and we discuss the need for the creation of AMMRs including their effective networking (AMMRNs), supporting data for which has been observed by studying coastal facilities subjected to strict access restrictions (for security reasons, not conservation). These facilities have acted as valuable proxies and, in reality, potentially act as AMMRs, as well as having a role in helping to detect and control invasive species. We discuss the ecological engineering aspects related to the design and type of materials used in coastal constructions with a view to aiding the integration of these into existing coastal ecosystems as well as promoting greater settlement of species and therefore increases in biodiversity. Finally, the environmental implications of AMMRNs within the future implementation strategy of the Water Framework Directive 2000/60 EC are also discussed.  相似文献   
78.
目前多数工程化人脸识别系统是基于子空间算法的,针对子空间算法识别系统中稳定性和抗干扰性不高的问题,从图像预处理的角度出发,通过Matlab仿真Eigenface和Fisherface两种算法识别过程,建立起图像差值模型,同时引入不同预处理方法进行比较,根据类间距离和类内距离的变化,从中确定出最优的预处理方法,改善算法识别率和效率,实验结果表明,加入合适的图像预处理可以增强识别系统的强壮性.  相似文献   
79.
《The Journal of geography》2012,111(6):249-262
Abstract

University students participated in a research project on communities and conservation on Mount Kilimanjaro in Tanzania. Students contributed by gathering data with various methods that will be compiled in a GIS. Living in three villages at different elevations on the mountain, students facilitated GPS mapping, a random survey of over 90 households, and recording of observations and interviews with the people of these villages. While the inclusion of students in the research project brought greater logistical demands, their participation allowed quick collection of data on a broad scale, more intimate knowledge of the three villages and the communities in them, and provided a valuable learning experience for the students with opportunities to develop and carry-out a research project in an international setting.  相似文献   
80.
Quantifying correlation between the spatial patterns of natural wetland plants and environmental gradient gives better understanding of wetland habitats, which is the fundamental for the strategy making on the protection and restoration of natural wetlands. In this study, the spatial patterns of wetland plants and the environmental gradient of wetland habitats were assessed in the Honghe National Nature Reserve (HNNR) in Northeast China, a wetland of international importance on the Ramsar list. Biophysical parameters’ values of wetland plants were obtained by field sampling methods, and wetland mapping at the community scale was completed using remote sensing techniques. Digital delineation of the surface water system, hydrological zoning and wetness index were produced by spatial analysis methods in Geographic Information System. An ecological ordination method and two clustering methods were used to quantify the relationship between the spatial distribution patterns of wetland plants and the corresponding environmental gradients. Such quantitative analyses also present the specific diversity of different types of wetland plants based on the environmental attributes of their habitats. With the support from modern geo-information techniques, the experimental results indicate how four ecotypes of wetland plants spatially transit from forest swamp, shrub wetland and meadow into marsh wetland with increasing wetness index and water table. And they also show how wetland spatial distribution patterns are controlled by an environmental gradient of wetness. Another key finding of this research work is that our results present the exact fundamental differences between marsh and non-marsh plants of 11 wetland plant communities within the core study area. Hence, this case study gives a good sample for better understanding of the complex correlation between the spatial patterns of wetland plants and their environmental attributes using advanced digital analysis methods. It is also useful to show how to integrate geoinformatic techniques with statistical analysis methods based on the field data base.  相似文献   
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