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滤纸薄样片—X射线荧光光谱法测定钨和锡   总被引:2,自引:0,他引:2  
荆照政  张博仪 《岩矿测试》1990,9(4):272-273
本文用蜡环成形滤纸定量吸附由微量进样器分取的50μl试液,制成薄样进行X射线荧光光谱分析,实现了对样品中高含量WO_3、SnO_2的定量测定。被测组份的荧光强度与浓度在0—500μg/50μl范围内有良好线性关系。方法操作简单、制样速度快、成本低、稳定性好。  相似文献   
2.
Xia  Xiaolong  Zhang  Xiong  Fayek  Sara  Yin  Zhaozheng 《Acta Geotechnica》2021,16(12):3779-3791

Photogrammetry-based method is gaining popularity in many fields. One of the main tasks of photogrammetry is to identify the homologous points in multiple images, which is commonly referred to as the corresponding problem. Coded targets are often placed on the surfaces of the targeted objects and have been widely used as a reliable method for solving the corresponding problem in photogrammetry for high-accuracy three-dimensional measurements. Automated recognition and identification of coded targets are of great importance in the coded target-based photogrammetry. However, false coded target identifications are inevitable due to large perspective distortion, unfavorable lighting conditions, and low-resolution, low-quality images, etc. As a result, manual corrections are often required, which are tedious, prone to error, and inefficient. In this paper, a faster R-CNN-based method has been proposed to recognize coded targets. Then, a table method has been developed to automatically identify and reject the falsely identified coded targets by taking advantages of the prior knowledge of the geometric arrangement of the coded targets. Based on that, missing coded targets can be recovered using either interpolation or extrapolation method. The effectiveness and accuracy of the proposed method are validated by implementing it into three-dimensional reconstruction of soil specimens during triaxial testing in geotechnical engineering. Experimental validation results indicate that the proposed method can achieve accurate and efficient coded target recognition and identification.

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3.
利用2008年夏季和冬季的海流资料分析了红海湾西北海区潮流性质、运动形式、涨落潮流特性、余流特征。结果表明: 红海湾西北海区属不规则半日潮海域, 潮流性质属往复流, 大致呈东—西向往返运动, 具有一定的旋转流性质; 平均涨潮流最大可达17.8cm·s-1, 平均退潮流最大可达19.3cm·s-1; 实测流受风和地形影响明显。余流受风和地形的影响也比较明显, 在偏北风作用下, 余流流向西偏南; 在偏南风作用下, 余流流向东偏北, 余流最大可达18.9cm·s-1。潮能主要由东部向西传播至红海湾西北海区, 潮能进入量值可达4.8×103W·m -1。  相似文献   
4.
周哲  胡钊政  李娜  肖汉彪  伍锦祥 《测绘学报》2021,50(11):1574-1584
针对地下停车场环境GPS信号缺失的问题,本文在环视特征地图构建的基础上,提出基于二阶马尔科夫模型的粒子滤波定位算法(Markov model-particle filter,MM-PF),实现智能车在地下停车场环境中的高精度定位.在该模型中,环视特征地图节点被定义为粒子,查询图像被定义为观测数据.在状态转移过程中,引入二阶马尔可夫模型,对短时间车辆运动进行建模,构建状态转移模型.利用图像的全局特征建立当前车辆获取的图像与各粒子(环视地图节点)之间的匹配关系,从获取的汉明距离建立粒子权重分布模型,可以大幅提高系统的计算效率.当前车辆的位置由局部特征匹配获得.选取两个典型的地下停车场场景对本文算法进行验证,在选取的两个场景中,本文算法平均定位精度小于0.38 m,定位误差均方差小于0.29 m,定位误差在1 m以下的概率不低于95.4%.试验结果表明:本文所提出的二阶MM-PF算法能够将车辆的运动信息与视觉信息相融合,相较于对比算法,定位精度与稳健性得到大幅提高.  相似文献   
5.
Geng  Wu  Cheng  Feng  Xie  Qiang  Zou  Xiaoli  He  Weihong  Wang  Zhaozheng  Shu  Yeqiang  Chen  Gengxin  Liu  Danian  Ye  Dong  Wang  Ruiwen  Liu  Chuanyu 《中国海洋湖沼学报》2020,38(6):1729-1745
Journal of Oceanology and Limnology - An ensemble-based method for the observation system simulation experiment (OSSE) is employed to design optimal observation stations and assess the present...  相似文献   
6.
Dissolved oxygen (DO) is a very important factor controlling the nitrogen cycle in wetlands. However, it is still unclear to what extent the presence of ammonia-oxidizing archaea (AOA) and bacteria (AOB), and related nitrification, are influenced by DO in estuarine wetlands. The aims of this study were to determine changes of nitrification at the sediment–water interface, to examine the abundance and diversity of archaeal and bacterial ammonia oxidizers in estuarine sediments, and to identify the correlation between nitrification and ammonia-oxidizing microorganisms along a simulated dissolved oxygen gradient in a Chinese estuarine wetland. The results showed that the nitrification rate was positively correlated with the diversity and abundance of AOA but not AOB, and the abundance and diversity of AOA can explain 87 % of the total variance of the first axes in the redundancy analysis. This indicates that AOA were primarily involved in ammonia oxidation in this study. Additionally, AOB were much more influenced by DO than AOA inferred from the assessment of dominant species and principal coordinates analysis of AOA and AOB. Higher diversity and abundance of AOA occurred in the mangrove sediments, which explain the higher nitrification rates in the mangrove sediments compared to the bare mudflat sediments. Notably, the trend of nitrification rate in the bare mudflat sediments was different from that in the mangrove sediments, suggesting that the extent of nitrification as impacted by DO depends largely on the sediment biotic and nutrient properties, and its environmental conditions including DO levels.  相似文献   
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