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81.
花岗岩类谱系填图法的指导思想,是从解体大岩基入手,建立同源岩浆演化的等级体制及其与岩石地层单位的对应关系,逐步实现按地质构造背景划分花岗岩的区划.该方法在苏州西部地区的区调工作中获得了较好的成效.从丰富多姿的侵入接触关系,建立了该区花岗岩的谱系,论证了主体花岗岩的产状是向北缓倾的岩席,进而,探讨了控岩构造和侵位机制.阐述了花岗岩与矿产的时空关系,并用热力驱动成矿说(HHP理论)解释了苏州各类高岭土矿的成因. 相似文献
82.
目的研究提高飞行器结构地面试验有效性的途径。方法计算同一被试件结构在飞行状态和地面试验状态下的有限元模型,测量地面试验状态下的模态以验证有限元模型的正确性;计算各特征点(也可以是遥测点)在天地状态下的响应,用机器学习法获取各特征点的映射关系模型;基于该模型由飞行点响应(或遥测数据)确定出地面试验件对应点的响应,并用载荷反求法得到它们的等效载荷;最终确定施加在试验系统上的载荷。结果以细长体结构为例,所得到由其组成试验系统的有限元模型与实测模型之间的固有频率最大相对误差为6.76%,利用映射关系模型预测出对应点在飞行状态下的振动响应。确定了飞行状态下结构响应的特征点,由地面试验系统所对应的响应点反推出应施加的载荷为60 N。结论利用天地数值计算-地面试验验证联合法,无需在地面试验状态下刻意模拟飞行状态的边界条件,确定出所需要施加的载荷,从而提高了飞行器地面试验的有效性。 相似文献
83.
随着我国经济、工业化、城市化进程迅速发展,PM_(2.5)污染在中国已经成为一个极端的环境和社会问题,并引起广泛关注.采用新技术估算的地表PM_(2.5)质量浓度,收集并处理了遥感反演的气溶胶光学厚度(AOD),气象数据,其他地理数据和污染物排放数据,采用贝叶斯最大熵(BME)结合地理加权回归(GWR)来分析2015年冬季的PM_(2.5)暴露在我国东部大范围区域的时空变异特征.结果表明,BME模型的十折交叉验证结果的决定系数R~2为0.92,均方根误差(RMSE)为8.32μg·m~(-3),平均拟合误差(MPE)为-0.042μg·m~(-3),平均绝对拟合误差(MAE)为4.60μg·m~(-3),与地理加权回归模型的结果相比(R~2=0.71,RMSE=15.68μg·m~(-3),MPE=-0.095μg·m~(-3),MAE=11.14μg·m~(-3)),BME的预测结果有极大的提高.空间上,PM_(2.5)高浓度地区主要集中在华北、长江三角洲、四川盆地,低浓度地区主要集中在中国的最南部如珠江三角洲和云南的西南部;时间上,不同月份的研究区域PM_(2.5)空间分布所有差别,2015年的12月、2016年1月PM_(2.5)污染最为严重,2015年的11月,2016年的2月污染相对较低. 相似文献
84.
Participatory ecosystem services scenarios can be used to inform decision making on the sustainable or wise use of biodiversity and ecosystem services (ES). To establish the plausibility and coherency of the recently constructed Biscay participatory scenarios, and to analyze policy options for improving sustainability of land use and the supply of ecosystem services, a spatially explicit analysis of land cover change was carried out. The modelling used an innovative methodology which included feedback from key stakeholders. Our study showed that scenario mapping can be a way of testing the credibility and internal consistency of scenarios, and a methodology for making them more coherent; it was also useful for highlighting land use trade-offs. The sustainability analysis for the ES supply side showed the benefits of promoting two land use/cover trends in the Biscay region: (i) an increase of sustainable arable land in the valley zones to reinforce biocapacity and self-provisioning while preserving agroecosystems’ ES flow; and (ii) natural forest regeneration in mountainous and other zones to increase carbon storage and sequestration while enhancing biodiversity and other ES flows. We argue that even if already protected public agro-forest lands may be the best places to start promoting these changes, additional measures are needed to involve private landowners and guarantee changes at a landscape level. Finally, we reflect on the need to make complementary analyses of ES supply and demand as a way of contributing to a broad sustainability agenda. 相似文献
85.
Despite increasing interest in learning from Indigenous communities, efforts to involve Indigenous knowledge in environmental policy-making are often fraught with contestations over knowledge, values, and interests. Using the co-production of knowledge and social order (Jasanoff, 2004), this case study seeks to understand how some Indigenous communities are engaging in science-policy negotiations by linking traditional ecological knowledge (TEK), western science, and other knowledge systems. The analysis follows twenty years of Indigenous forest management negotiations between the Xáxli’p community and the Ministry of Forests in British Columbia (B.C.), Canada, which resulted in the Xáxli’p Community Forest (XCF). The XCF is an eco-cultural restoration initiative that established an exclusive forest tenure for Xáxli’p over the majority of their aboriginal territory—a political shift that was co-produced with new articulations of Xáxli’p knowledge. This research seeks to understand knowledge co-production with Indigenous communities, and suggests that existing knowledge integration concepts are insufficient to address ongoing challenges with power asymmetries and Indigenous knowledge. Rather, this work proposes interpreting XCF knowledge production strategies through the framework of “Indigenous articulations,” where Indigenous peoples self-determine representations of their identities and interests in a contemporary socio-political context. This work has broader implications for considering how Indigenous knowledge is shaping science-policy negotiations, and vice versa. 相似文献
86.
Jihoon Park Moon Seong Kang Inhong Song 《Journal of the American Water Resources Association》2015,51(3):859-876
The objective of this article was to assess flood vulnerability based on the representative concentration pathways (RCP) scenarios at city and county levels. A quantile mapping method was adopted to correct bias that is inherent in climate change scenarios. A series of proxy variables related to climate exposure, sensitivity, and adaptive capacity were chosen to assess flood vulnerability. Proxy variables were standardized using the Z‐score method. Principal component analysis was carried out to calculate the weighting of proxy variables. The study area was the Korean peninsula. The spatial resolution was on a city and county basis and the temporal resolution was 1990s, 2025s, 2055s, and 2085s (divided into 1976‐2005, 2011‐2040, 2041‐2070, and 2071‐2100). In the spatial comparison, we found that the areas with high‐level flood vulnerability increased over time in the central region, including metropolitan areas, and near the southern coast. In the temporal comparison, we found that the RCP4.5 scenario showed a tendency to increase steadily and the RCP8.5 scenario showed a tendency to decrease in the 2055s slightly and increase again in the 2085s. The study findings may provide useful data for the determination of priority for countermeasure development, though robustness of these findings with additional future projections should be established. 相似文献
87.
Effects of surrounding land use and water depth on seagrass dynamics relative to a catastrophic algal bloom 下载免费PDF全文
Seagrasses are the foundation of many coastal ecosystems and are in global decline because of anthropogenic impacts. For the Indian River Lagoon (Florida, U.S.A.), we developed competing multistate statistical models to quantify how environmental factors (surrounding land use, water depth, and time [year]) influenced the variability of seagrass state dynamics from 2003 to 2014 while accounting for time‐specific detection probabilities that quantified our ability to determine seagrass state at particular locations and times. We classified seagrass states (presence or absence) at 764 points with geographic information system maps for years when seagrass maps were available and with aerial photographs when seagrass maps were not available. We used 4 categories (all conservation, mostly conservation, mostly urban, urban) to describe surrounding land use within sections of lagoonal waters, usually demarcated by land features that constricted these waters. The best models predicted that surrounding land use, depth, and year would affect transition and detection probabilities. Sections of the lagoon bordered by urban areas had the least stable seagrass beds and lowest detection probabilities, especially after a catastrophic seagrass die‐off linked to an algal bloom. Sections of the lagoon bordered by conservation lands had the most stable seagrass beds, which supports watershed conservation efforts. Our results show that a multistate approach can empirically estimate state‐transition probabilities as functions of environmental factors while accounting for state‐dependent differences in seagrass detection probabilities as part of the overall statistical inference procedure. 相似文献
88.
应用陆地卫星TM图象编制闽北土壤图(1:10万)的方法研究 总被引:1,自引:0,他引:1
以TM原图象合成的标准假彩色和似自然色图象作目视解译为主,根据土壤及其相关地物的野外光谱测定数据,分析其影象色调特征;用TM 7个波段原始黑白图象作对比解译,以预测不同地物的彩色合或效果并选择最佳合成方案;用TM6热红外图象作假彩色等密度分割处理,以提取随海而异的地面温度场和土壤类型垂直分带信息;用TM比值图象及其假彩色合成处理,以逐步增强并提取土壤信息;最后参照同比例尺地质图和地形图等相关资料,完成土壤图的编制。 相似文献
89.
90.
1:1000000中国草地资源图的编制与研究 总被引:7,自引:0,他引:7
编制1:1000000中国草地资源图(以下简称《草地图》)是"1978~1985年中国科学技术发展规划"中的一项重点研究课题。首先在全国约800万km2草地分布区的2000多个县内进行野外实地调查和产草量测定,辅以航、卫片校核,编绘县级1:5万或1:10万草地类型图、草地等级图、草地利用现状图。然后采用系列制图方法,遵照全国统一的编制规范和制图综合原则,用上述县级草地图逐级缩编成国家级1:100万草地资源图。该图在不同的制图区域──牧区、半农半牧区、农区有不同的地理要素选择标准;不同的图斑表现级;不同的最小图斑面积。《草地图》除传统地表现草地植被类型外,还表现草地利用性状,按制图单元进行草地等级评价。用变距等高距选取了少量对划分草地类型界线、重要牧草分布界线、季节草地界线有重要指示意义的等高线。 相似文献