柴达木盆地西部地区渐新世沉积物源分析   总被引：2，自引：0，他引：2       下载免费PDF全文

王艳清宫清顺  夏志远熊绍云 《中国地质》2012,39(2):426-435

沉积物源分析在确定沉积物源位置、母岩性质及沉积物搬运距离,甚至整个盆地的沉积作用和构造演化等方面都有重要意义。本文从重矿物组合、轻矿物组合、稀土元素分配和古水流恢复等方面系统地分析了柴达木盆地西部地区渐新世物源方向,确定了阿尔金东段物源、阿尔金西段物源、阿拉尔物源、铁木里克物源、祁漫塔格—东柴山物源和弯西—甘森物源6大沉积物源。沉积物源特征明显控制了沉积物特征,来自阿尔金西段物源的沉积物搬运距离短,碎屑物供给明显受季节性洪水控制,故稳定性差,发育近源陡坡型的扇三角洲、近岸水下扇沉积物;来自其余物源的沉积物搬运距离较长,最长搬运距离约190 km,碎屑物供给的稳定性较好,发育远源缓坡型的辫状三角洲沉积物,受不同沉积物源的影响,其沉积特征具有明显的差异性。  相似文献   

Nitrogen uptake in light versus darkness of the seagrass Zostera noltei: integration with carbon metabolism          下载免费PDF全文

Ana Alexandre  João Silva  Rui Santos 《Marine Ecology》2016,37(5):1050-1056

We conducted a study that shows that light and dark conditions do not affect the uptake rates of ammonium and nitrate by the seagrass Zostera noltei. This is an important advantage over some seaweed species in which these rates are severely reduced at night. In the light, the ammonium uptake rates were initially higher (15 and 20 μmol·g^?1·h^?1) and stabilized at a rate of 5 μmol·g^?1·h^?1 after 1 h, whereas in the dark the rates remained constant at a rate of 10 μmol·g^?1·h^?1 over the first 180 min of incubation. The rates of nitrate uptake in the light were high within the first 120 min of incubation (7.2–11.1 μmol·g^?1·h^?1) and decreased afterwards to lower values (0.8–3.9 μmol·g^?1·h^?1), whereas in the dark the rates fluctuated around 0.0–11.1 μmol·g^?1·h^?1 throughout the whole incubation time (7 h). The soluble sugar content of Z. noltei leaves increased significantly with both ammonium and nitrate incubations in the light, indicating the metabolic outcome of photosynthesis. In the dark, there was no significant variation in either the soluble sugar or in the starch content of leaves, rhizomes or roots in either the ammonium or nitrate incubations. However, the total starch content of plants decreased at night whereas the total soluble sugars increased, suggesting a process of starch catabolism to generate energy with the consequent production of smaller monosaccharide products. The starch content of rhizomes decreased significantly during the light incubations with nitrate but not with ammonium. These results suggest that carbohydrate mobilization is necessary for Z. noltei to account for extra energetic costs needed for the uptake and assimilation of nitrate. Furthermore, our results suggest that nitrate uptake, at least during the day, requires the mobilization of starch whereas the uptake of ammonium does not.  相似文献   

单条胶黏藻(Dumontia simplex Cotton)孢子早期发育及其生活史的研究     

姜朋  赵树雨  李芳  王宏伟 《海洋与湖沼》2016,47(1):151-157

为研究单条胶黏藻(Dumontia simplex Cotton)的孢子发育类型和生活史,探明其孢子发育的最适环境因子,在实验室条件下,通过培养观察,研究不同温度、光照强度和盐度对其孢子(果孢子和四分孢子)早期发育的影响。结果表明:(1)孢子发育过程中无丝状体出现,孢子的发育类型为直接盘状体型。(2)温度、光照强度和盐度对其孢子的早期发育均有影响,温度6—30°C范围内,果孢子发育的最适温度为9°C,四分孢子为9—12°C;光强80—400μmol/(m2·s)范围内,果孢子发育的最适光强为160μmol/(m2·s),四分孢子为160—200μmol/(m2·s);盐度15—50范围内,孢子(果孢子和四分孢子)发育的最适盐度为30。(3)单条胶黏藻生活史由单倍的雌、雄配子体和二倍的果孢子体及四分孢子体构成,配子体和四分孢子体外形一致,交替出现,属于典型的同型世代交替。  相似文献   

Metamerism Appreciation of Jadeite-Jade Green under the Standard Light Sources D65, A and CWF     

GUO Ying  WANG Huan  LI Xiang  DONG Shirong 《《地质学报》英文版》2016,90(6):2097-2103

We tested 288 pieces of the polished cabochon jadeite-jade with high quality green and smooth surfaces using the colorimeter Color i5 based on the CIE 1976 L~*a~*b~* uniform color space. The color changes after alternating three CIE standard light sources D_(65),A and CWF were compared,and the degree of metamerism was evaluated. The results show that the CIE standard light sources D_(65),A and CWF increase the chroma of green and turn bluish green into vivid green,which are similar or to nearly colorless and transparent glass-like samples with fine textures. When the three light sources were individually alternated,the lightness of the jadeite-jades showed little change,but the tone changed significantly. Metamerism occurred only in 3 pairs among the 16 samples that were selected by cluster analysis for quality,and the metamerism colors were highly consistent of L~*D_(65)∈(43.47,46.75),C~*D_(65)∈(65.20,68.80) and ho~*D_(65)∈(138.10,140.23). We can conclude that the jadeite-jade green gradually turns to blue when the color temperature of the light source increases. But when considering both the light sources and the samples,D_(65) is more suitable to be the light source of jadeite-jade green when compared with the light sources CWF and A. Compared with the CIE standard green and high chroma green,high-quality jadeite-jade green has a slight yellow tone,low lightness and high chroma. The special metamerism index decreased to 1 when the light source alternated among D_(65),A and CWF. Therefore,the color of jadeite-jade green might be slightly influenced by alternating of the light sources.  相似文献   

圆明亮琢型立方氧化锆在环形光源下的亮度测量研究     

刘萍萍  袁心强  石斌  王亚军 《地质科学译丛》2014,(1):62-69

运用钻石光学效果观察仪采集合成立方氧化锆（CZ）样品的光学效果的实测图样,采用中国地质大学（武汉）珠宝学院石斌博士研发的宝石切工仿真分析系统模拟样品的光学效果仿真图样及可视亮度。通过量化程序统计样品实测图样的亮度值,以及仿真图样的亮度值。研究在入射角度为7．12°-12．58°的环形光源下,样品的实测亮度与主要切工参数的关系;对比仿真图样与实测图样的异同;分析样品可视亮度与仿真图样的统计亮度值的变化趋势,发现样品仿真图样的统计亮度值与模拟的可视亮度变化趋势基本一致;对称性较好样品的仿真图样与实测图样较一致;亭角38．5°-41．5°,冠角27°-39°之间一些特定组合的样品具有较高的亮度。结果表明,通过采集、分析图样测量圆明亮琢型宝石实际亮度的方法是准确可行的;对称性或某些参数的细微变化都可能引起样品亮度很大的变化;亮度较高样品的亭角、冠角满足加和规律,即亭角减小必须与需锫增加相静会．才鲐呈拥掂高的毒序  相似文献   

广西岑溪糯垌稀土矿床地质特征及成矿规律     

黄长帅  廖航  卢见昆  吴继炜 《矿产与地质》2014,(5):551-554

文章阐述了岑溪糯垌稀土矿床地质特征及其矿石特征、矿石有用组分含量及变化规律、矿石化学成分、矿石浸取率及稀土元素配分类型等,认为岑溪糯垌稀土矿床属黑云钾长(二长)花岗岩风化壳离子吸附型稀土矿床,稀土元素配分类型为低铕富镧钕轻稀土型,矿层主要赋存于花岗岩全风化层中。  相似文献   

融合无人机影像与LiDAR点云的山区地表覆被景观特征探测     

高莎  袁希平  甘淑  杨明龙  袁新悦  罗为东 《测绘通报》2022,(1):110-115

机载LiDAR数据能够准确提供对象的三维空间位置信息,无人机高分辨影像具备丰富的色彩信息与纹理信息,综合两种数据的优点,可进行数据集成融合。针对山区普遍存在的分布广泛的植被覆盖类型基质景观,本文通过构建可见光植被指数（VDVI）融合光谱信息点云数据,进行典型植被特征提取的研究。为了验证该方法提取信息的准确度,分别构建了3种数据源并依次进行山区地表植被提取试验。对试验结果定性定量分析表明,融合光谱点云数据的植被覆被率为56.8%,较另外两种数据类型的植被覆被率更加接近参考值（58.2%）,可信度相对较高,效果更好,植被图斑轮廓更加清晰,更适用于目标对象植被特征提取,使融合影像信息的点云数据分类优势得以体现,证实了该方法面向山区植被特征提取的可行性。  相似文献   

基于逐日夜间灯光遥感的新冠肺炎疫情变化信息快速提取——以北京市为例     

江泽霖  邓健  栾海军  李兰晖 《测绘通报》2022,(7):43-48

针对国内外日益复杂的疫情形势,本文以2020年6月北京疫情为例,利用NPP-VIIRS卫星的逐日夜间灯光数据,分析疫情受影响区域及疫情的控制与恢复状况,探索与人口密度等社会经济因素的关系。研究结果表明,逐日夜间灯光遥感可以有效提取疫情影响的区域范围及反映该区域受影响程度,所提取的受影响区域与国家划定的中高风险区域情况一致;同时基于逐日夜间灯光遥感能够及时监测疫情发展及疫情防控措施状况,区域夜间灯光强度随着疫情及防控的进展呈现明显的变化;平均夜间灯光损失强度及恢复强度同疫情暴发期区域人口密度均具有较强的相关性,相关性指标R²分别为0.97和0.91。本文研究结果表明逐日夜间灯光影像在快速提取新冠肺炎疫情变化信息方面有较大潜力。  相似文献   

整合DMSP/OLS和NPP/VIIRS夜间灯光遥感数据的长江三角洲城市格局时空演化研究     

许正森  徐永明 《地球信息科学学报》2021,23(5):837-849

本文基于1992—2012年DMSP/OLS和2012—2018年NPP/VIIRS夜间灯光遥感数据,对长江三角洲城市群时空演化格局进行监测。考虑到不同卫星夜间灯光遥感数据之间的不一致性以及城市核心区亮度过饱和问题,对DMSP/OLS和NPP/VIIRS数据进行连续性校正、去饱和处理和一致性校正,构建长江三角洲区域1992—2018年长时间序列多源夜间灯光遥感数据集。利用二分法基于该数据逐年提取长江三角洲城市群各城市建成区空间分布,计算加权标准差椭圆和Zipf系数进行重心变化和方向性分布变化、规模体系变化等监测。结果表明： ① 本研究采用的连续性校正、去饱和处理和一致性校正方法能够构建稳定的长时间序列多源夜间灯光遥感数据集; ② 基于二分法提取的建成区面积平均绝对误差为6.85 km²,平均相对误差为8.10%; ③ 长三角城市群重心较为稳定,始终在苏州市境内的太湖沿岸附近,呈现出向东南方向移动的趋势城市群呈西北—东南方向分布,且分布方向有向南北方向转动的趋势,标准差椭圆的扁率持续减小,表明城市群的方向性分布减弱; ④ Zipf系数始终在1附近且呈缓慢降低的趋势,城市规模分布较为均衡。  相似文献   

Mechanical Behavior of Light-Weight Soil Under Consolidated Drained Shear Condition     

Tian-Shun Hou  Wei Wang  Ya-Sheng Luo  Jin-Qian Dang  Xiu-Juan Yang 《Marine Georesources & Geotechnology》2013,31(3):264-276

To reveal the influence of material composition on mechanical properties of light-weight soil, stress-strain -volumetric strain characteristics and Poisson's ratio of mixed soil were researched by consolidated drained shear tests. The results show that light-weight soil is a kind of structural soil, so its mechanical properties are affected by mixed ratio and confining pressure, and mixed soil possesses structural yield stress. When confining pressure is less than the structural yield stress, strain softening occurs; when confining pressure is more than the structural yield stress, strain hardening is observed. There are two kinds of volume change behavior: shear contraction and shear dilatancy. Shear dilatancy usually leads to strain softening, but there isn't an assured causal relationship between them. Poisson's ratio of mixed soil is a variational state parameter with the change of stress state, it decreases with increased confining pressure, and it increases with increased stress level. When axial strain is near 5%, Poisson’ ratio is gradually close to a steady value. The main range of Poisson's ratio is 0.25～0.50 when confining pressure changes from 50 to 300 kPa. When unconfined compressive strength of mixed soil is less than 328 kPa, its stress-strain-volumetric strain characteristics can be predicted very well by Duncan-Chang model (E-B model). However, when the range of unconfined compressive strength is [328 kPa, 566 kPa], the model can't predict stress-strain characteristics accurately when confining pressure is under 200 kPa, and it also can't predict the strong shear dilatancy phenomenon of mixed soil under low confining pressure.  相似文献