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排序方式: 共有145条查询结果,搜索用时 43 毫秒
81.
福建紫金山铜矿床属高硫浅成中低温热液矿床,矿石中主要含铜矿物为蓝辉铜矿、铜蓝和硫砷铜矿等,且铜矿物与黄铁矿密切共生。由于铜矿石中硫含量较高,导致铜精矿中硫含量超标,w(S)/w(Cu)比值为2.0~2.1,远高于冶炼要求的1.15~1.20,影响其经济价值。使用X射线荧光(XRF)光谱分析对紫金山铜矿中S元素的分布进行数字化研究,查明硫的空间分布规律和赋存状态,划分铜矿石类型,为紫金山铜矿今后的采选工作提供参考。 相似文献
82.
Seasonal variations and bioavailability of inorganic phosphorus in soils of Yeyahu Wetland in Beijing, China 总被引:4,自引:0,他引:4
Phosphorus (P) in soils has an important influence on the development and productivity of wetland. The objective of this study was to investigate the distribution, bioavailability and seasonal variations of inorganic phosphorus (IP) in soils of Yeyahu Wetland. The results showed that the concentration of Ca-bound P (Ca-P) remained the main occurrence in all IP fractions despite the season, at the same time the Al-bound P (Al-P) was always the lowest IP fraction despite the season. Al-P and Fe-bound P (Fe-P) concentration were all reached the highest value in May and the lowest in November, which was opposite to the occluded P (Oc-P) fraction. The notable higher Oc-P concentration in November observed in this study was probably due to the decomposition of plants and the subsequently releasing of oxides to soils. Ca-P didn't change much with season variations. Exchangeable P (Ex-P) and Oc-P were all positively correlated with soil moisture content and organic matter content, but Al-P was negatively correlated with these two soil properties. As a stable form, Ca-P was not associated with soil properties. Al-P, Fe-P and Ca-P might contribute to the storage of P in studied wetland with the principle component analysis results. The concentration rank order of the bio-available P in soils was generally as follows: Olsen-P > Algal available P (AAP) > Water soluble P (WSP) > Readily desorbed P (RDP). Olsen-P was positively correlated with Ex-P and Oc-P, and it was thought to be a more suitable indicator for bio-available P in soils. 相似文献
83.
FY-3A/MERSI数据在山东省农田干旱监测中的应用 总被引:1,自引:0,他引:1
干旱是影响社会发展和农业生产的主要气象灾害之一。利用中国新一代极轨气象卫星FY-3A上搭载的250 m中分辨率光谱成像仪(MERSI)数据,基于垂直干旱指数(PDI),结合山东省旱情统计数据,建立了适合山东省的PDI干旱指数分级标准,在此基础上对山东省2010~2011年秋冬季的干旱状况进行了监测,并将监测结果与同期的降水、温度和干旱监测资料以及19个国家级农气站的土壤相对湿度资料进行对比分析。结果表明:基于FY-3A/MERSI 250 m分辨率卫星资料计算的PDI能够客观反映山东省旱情的空间分布和动态发展过程。PDI与对应实地观测的10 cm、20 cm土壤相对湿度之间有较好的负相关性,且20 cm的土壤相对湿度较10 cm的土壤相对湿度与PDI的相关关系更稳定。因此,利用FY-3A/MERSI卫星资料监测山东省干旱状况具有可行性,适于在干旱监测业务中推广应用。 相似文献
84.
Exploring the effects of water on vegetation change and net primary productivity along the IGBP Northeast China Transect 总被引:2,自引:0,他引:2
To understand the mechanisms underlying the effects of climate variation, especially the effects of water on vegetation, vegetation
type and distribution as well as climate data and soil type were used to simulate present vegetation distributions and net
primary productivity (NPP) under present and future climate scenarios SRES-A2 and SRES-B2. A natural vegetation NPP model
was also applied to calculate future vegetation NPP. The results showed that water played a dominant role not only in the
distribution of vegetation, but also in the rate of change in the vegetation area. Analysis of NPP showed that precipitation
had more effects on the amount of biome NPP than temperature did. Different effects were observed for the rate of change in
NPP. In cases where biomes remain unaltered, the variation in annual precipitation could account for 39% of the variation
in NPP. In cases where biomes changed, 45% of NPP was caused by temperature variation. Regarding the variation in transect
production, −2.85% resulted from the change in vegetation structure when compared with present NPP, and 7.69% from the climate
change under scenario SRES-B2; these values were −7.4 and 19.56%, respectively, under scenario SRES-A2. The results showed
water served as a dominant factor controlling the vegetation distributions and NPP. However, temperature became determinant
where the biomes changed, impacting the rate of change in vegetation NPP when the climate changed. The results also showed
that water would have a positive effect on transect production, and the structure of vegetation had a negative effect under
the projected future climate. 相似文献
85.
Gang Chen Xianju Li Weitao Chen Xinwen Cheng Yujin Zhang Shengwei Liu 《Natural Hazards》2014,74(2):509-526
The aim of this study was to identify some new factors that may impact the occurrence and distribution of landslides based on light detection and ranging digital elevation model (LiDAR DEM), and to examine whether these factors can apply to distinguish between landslide and non-landslide pixels. Twenty-one landslide influential factors were identified. Thereinto, there were ten novel factors, namely the texture factors of slope and surface roughness, including the contrast (Con), correlation (Cor), angular second moment, entropy, and homogeneity (Hom) textures. Qualitative and quantitative analysis and feature selection method were applied to examine the application of these factors. The analysis results indicate that these factors have certain abilities to distinguish between landslide and non-landslide objects. And the selected optimal factors combination that derived from feature selection method was DEM, slope, Hom_d, Con_s, Cor_s, Hom_s, Con_r, Cor_r, and Hom_r (_d, _s, and _r represent DEM, slope, and surface roughness textures, respectively). In conclusion, the identified landslide influential factors can provide effective information for landslide identification. And the new texture factors of slope and surface roughness could act as important measurements that can improve the precision of landslide inventory mapping, susceptibility mapping, and risk assessment. 相似文献
86.
传统观点认为从烃源岩中分离出的干酪根是油气生成的母质,但它的处理方式破坏了有机质与矿物的原始赋存状态。为此,选取济阳坳陷埋深280~3 900m烃源岩,提取<2μm的有机黏粒复合体,研究其结构和生烃特征。有机黏粒复合体主要由蒙皂石和伊利石组成,TOC为2.62%~9.78%,经H2O2处理后TOC仍高达1.23%~4.63%,表明烃源岩中有机质主要富集在有机黏粒复合体中。有机黏粒复合体加热到250℃时,在XRD曲线上的衍射峰(d001)在1.3~1.4nm;加热至550℃时,衍射峰(d001)才移至1.0nm处;并且在DTA曲线上350℃附近的放热峰极其稳定,这些特征表明有机质进入到黏土矿物层间域。在PY-GC(热解—色谱)曲线上,烃源岩和有机黏粒复合体都在250~550℃释放C20—C30的有机组分,并在450℃释放量达到峰值。由此可见,烃源岩中的有机黏粒复合体,是烃源岩中有机质富集的主体,具有较好的稳定性,并释放出与原油特征相似的有机组分,表明它是具有巨大潜力的天然的生烃母质。 相似文献
87.
<正>Objective The Songnen masiff is located to the east of the Central Asian Orogenic Belt.The existence and rather the scale and nature of the Precambrian crystalline basement is controversial.Based on recent study of zircon U-Pb chronology,besides a minor number of Neoproterozoic strata,most of the so-called Precambrian metamorphic rock series,such as the Dongfengshan Group and the Zhangguangcailing Group,were formed in the Mesozoic 相似文献
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