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131.
随着我国核电工业建设步伐的加快,高放废物处置库的场址选择成为当前极为紧迫的课题。本文分析了甘肃北山高放废物处置库的选址现状,提出应加快相关核安全法规的建设以指导场址的选择;应对北山地区补充地震地质调查工作,特别是对区内的几条断层要进行断层能动性的研究。这对场址的适宜性是一个带有颠覆性的问题。 相似文献
132.
<正>Against the current background of global climate change,the study of variations in the soil carbon pool and its controlling factors may aid in the evaluation of soil's role in the mitigation or enhancement of greenhouse gas.This paper studies spatial and temporal variation in the soil carbon pool and their controlling factors in the southern Song-nen Plain in Heilongjiang Province,using soil data collected over two distinct periods by the Multi-purpose Regional Geochemical Survey in 2005—2007, and another soil survey conducted in 1982—1990.The study area is a carbon source of 1479 t/km~2 and in the past 20 years,from the 1980s until 2005.the practical carbon emission from the soil was 0.12 Gt.Temperature,which has been found to be linearly correlated to soil organic carbon,is the dominant climatologic factor controlling soil organic carbon contents.Our study shows that in the relevant area and time period the potential loss of soil organic carbon caused by rising temperatures was 0.10 Gt,the potential soil carbon emission resulting from land-use change was 0.09 Gt,and the combined potential loss of soil carbon(0.19 Gt) caused by warming and land-use change is comparable to that of fossil fuel combustion(0.21 Gt).Due to the time delay in soil carbon pool variation,there is still 0.07 Gt in the potential emission caused by warming and land-use change that will be gradually released in the future. 相似文献
133.
Uptake and recovery of soil nitrogen by bryophytes and vascular plants in an alpine meadow 总被引:2,自引:2,他引:0
Due to their particular physiology and life history traits, bryophytes are critical in regulating biogeochemical cycles and functions in alpine ecosystem. Hence, it is crucial to investigate their nutrient utilization strategies in comparison with vascular plants and understand their responses to the variation of growing season caused by climate change. Firstly, this study testified whether or not bryophytes can absorb nitrogen(N) directly from soil through spiking three chemical forms of 15N stable isotope tracer. Secondly, with stronger ability of carbohydrates assimilation and photosynthesis, it is supposed that N utilization efficiency of vascular plants is significantly higher than that of bryophytes. However, the recovery of soil N by bryophytes can still compete with vascular plants due to their greater phytomass. Thirdly, resource acquisition may be varied from the change of growing season, during which N pulse can be manipulated with 15N tracer addition at different time. Both of bryophytes and vascular plants contain more N in a longer growing season, and prefer inorganic over organic N. Bryophytes assimilate more NH4+ than NO3– and amino acid, which can be indicated from the greater shoot excess 15N of bryophytes. However, vascular plants prefer to absorb NO3– for their developed root systems and vascular tissue. Concerning the uptake of three forms N by bryophytes, there is significant difference between two manipulated lengths of growing season. Furthermore, the capacity of bryophytes to tolerate N-pollution may be lower than currently appreciated, which indicates the effect of climate change on asynchronous variation of soil N pools with plant requirements. 相似文献
134.
正森林土壤是陆地生态系统土壤中最大的碳库,约占全球土壤碳库的3/4,在全球C循环中起至关重要作用[1]。土壤异养呼吸(Heterotrophic respiration,Rh)是森林生态系统土壤碳库损失的主要途径。土壤异养呼吸是指土壤在微生物参与下的矿化过程,主要包括根际微生物呼吸、矿质土壤呼吸(无根土壤)和枯枝落叶层呼吸,由于土壤动物呼吸量不大,因此森林生态系统的异养呼吸主要表现为矿质土壤呼吸[2-4]。土壤异养呼吸具有高度的空间变异性,在全球范围内,异养呼吸所占总呼吸的比例为7%~83%,其中在热带和温带(30%~83%)森林生态系统中所占比例高于寒带地区(7%~ 相似文献
135.
海洋传感观测服务柔性开发技术研究 总被引:1,自引:0,他引:1
海洋传感观测服务能够实现多个海洋观测系统间的数据共享与集成,支持大范围、多学科的海洋科学研究。在软件开发过程中,由于不同观测系统的数据库异构互异,导致传感器观测服务软件难以复用,开发效率低。本文针对数据库结构的相似性进行分析,提出海洋传感观测服务的柔性开发模型,设计可适配于异构数据库的服务构件。该构件通过配置观测数据在具体数据库的存储结构,实现了数据库结构向服务模式定义的映射;服务构件根据配置信息生成数据库查询语句,实现观测数据的自动提取,避免了数据库异构导致的重复开发的问题。通过将服务构件应用在实际开发中,验证了该模型的有效性与可行性。 相似文献
136.
简单介绍了海南省基础地理信息数据库的物理设计和逻辑设计,包括数字线划图数据库、数字正射影像数据库、数字高程模型数据库、地名数据库以及元数据库五个子库的逻辑设计,以及数据库建库的步骤,包括数据入库前检查,数据库结构设计和数据入库。 相似文献
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