Graphic correlation method has been proved to be very useful in correlating sections in different places. In this study, we have selected five sections from the Western Interior Basin, USA and applied graphic correlat...Graphic correlation method has been proved to be very useful in correlating sections in different places. In this study, we have selected five sections from the Western Interior Basin, USA and applied graphic correlation method to correlate them. The selected five sections are located from the eastern to the western margins of the Western Interior Basin, USA. The cross-basinal high-precision chronostratigraphic correlation provides geologists a better understanding about how facies and depositional environments evolved across the mid-Cretaceous Western Interior Basin during the mid-Cretaceous. In addition, our data fits well with the previous understandings about mid- Cretaceous Western Interior Seaway, which characterized by slow depositional rates and higher organic matter concentration.展开更多
Three dimensional-digital image correlation(3 D-DIC) is a widely used optical metrology in the experimental mechanics community because of its reliability, practicality, and flexibility. Although the precision of digi...Three dimensional-digital image correlation(3 D-DIC) is a widely used optical metrology in the experimental mechanics community because of its reliability, practicality, and flexibility. Although the precision of digital image correlation(DIC) has been thoroughly studied theoretically and numerically, verification experiments have seldom been performed, especially for complex surfaces with a small field of view(FOV). In this work, the shape of a 1-yuan coin was measured using 3 D-DIC; the shape was complex due to the presence of many fine details, and the FOV was relatively small because the coin diameter was only 25 mm. During the experiment, a novel strategy for speckle production was developed: white paint was simply sprayed onto the surface. Black paint was not used; instead, taking advantage of the reflective nature of the coin surface, polarized light and a Polaroid filter were introduced, and the polarization direction was carefully adjusted, ensuring that the spray pattern was extremely thin and that high-quality speckle images with significant contrast were captured. The three-dimensional coin shape was also successfully determined for comparison using a stylus profiler. The results demonstrate that 3 D-DIC provides high precision in shape measurement even for complex surfaces with small FOV. The precision of 3 D-DIC can reach 1/7000 of the field of view, corresponding to about 6 μm in this experiment.展开更多
高频动态PPP(Precise Point Positioning)定位技术在高精度动态定位领域具有广泛的应用。由于PPP定位通常采用Kalman滤波进行数据处理,随着滤波次数的增加,标准Kalman滤波逐渐失去最优性,导致定位精度下降,甚至发散。针对这一问题,提出...高频动态PPP(Precise Point Positioning)定位技术在高精度动态定位领域具有广泛的应用。由于PPP定位通常采用Kalman滤波进行数据处理,随着滤波次数的增加,标准Kalman滤波逐渐失去最优性,导致定位精度下降,甚至发散。针对这一问题,提出一种利用时间差分定位技术提高高频动态PPP定位精度的新方法。理论分析及实验结果表明:该方法可以削弱高频动态PPP定位中滤波次数增加导致的定位精度下降,在一定程度上提高高频动态PPP定位的精度。展开更多
文摘Graphic correlation method has been proved to be very useful in correlating sections in different places. In this study, we have selected five sections from the Western Interior Basin, USA and applied graphic correlation method to correlate them. The selected five sections are located from the eastern to the western margins of the Western Interior Basin, USA. The cross-basinal high-precision chronostratigraphic correlation provides geologists a better understanding about how facies and depositional environments evolved across the mid-Cretaceous Western Interior Basin during the mid-Cretaceous. In addition, our data fits well with the previous understandings about mid- Cretaceous Western Interior Seaway, which characterized by slow depositional rates and higher organic matter concentration.
基金supported by the National Natural Science Foundation of China(Grant Nos.11332010,51271174,11372300,11127201,11472266&11428206)
文摘Three dimensional-digital image correlation(3 D-DIC) is a widely used optical metrology in the experimental mechanics community because of its reliability, practicality, and flexibility. Although the precision of digital image correlation(DIC) has been thoroughly studied theoretically and numerically, verification experiments have seldom been performed, especially for complex surfaces with a small field of view(FOV). In this work, the shape of a 1-yuan coin was measured using 3 D-DIC; the shape was complex due to the presence of many fine details, and the FOV was relatively small because the coin diameter was only 25 mm. During the experiment, a novel strategy for speckle production was developed: white paint was simply sprayed onto the surface. Black paint was not used; instead, taking advantage of the reflective nature of the coin surface, polarized light and a Polaroid filter were introduced, and the polarization direction was carefully adjusted, ensuring that the spray pattern was extremely thin and that high-quality speckle images with significant contrast were captured. The three-dimensional coin shape was also successfully determined for comparison using a stylus profiler. The results demonstrate that 3 D-DIC provides high precision in shape measurement even for complex surfaces with small FOV. The precision of 3 D-DIC can reach 1/7000 of the field of view, corresponding to about 6 μm in this experiment.
基金supported by the National Natural Science Foundation of China (12101559)the Zhejiang Natural Science Foundation (LQ22A010013)+1 种基金the Science Foundation of Zhejiang Sci-Tech University (21062111-Y)the Scientific Research Foundation of Zhejiang Sci-Tech University。
文摘高频动态PPP(Precise Point Positioning)定位技术在高精度动态定位领域具有广泛的应用。由于PPP定位通常采用Kalman滤波进行数据处理,随着滤波次数的增加,标准Kalman滤波逐渐失去最优性,导致定位精度下降,甚至发散。针对这一问题,提出一种利用时间差分定位技术提高高频动态PPP定位精度的新方法。理论分析及实验结果表明:该方法可以削弱高频动态PPP定位中滤波次数增加导致的定位精度下降,在一定程度上提高高频动态PPP定位的精度。
