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CMM测量扫描线型数据平滑方法的研究 被引量:3
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作者 锁小红 崔凤奎 +1 位作者 王晓强 张丰收 《煤矿机械》 北大核心 2005年第3期25-26,共2页
介绍了由CMM测量得到扫描线型数据的光学原理以及对得到数据进行平滑滤波的必要性 ,建立了扫描线型数据的数学模型 ,讨论并分析了常用的 3种平滑滤波算法及其优缺点 。
关键词 CMM 扫描线型数据 平滑滤波
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压电超声共振式风传感器风场闭环解算策略研究 被引量:2
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作者 曾祥豹 胡义东 +4 位作者 王露 王飞 廖崧琳 胡杨 袁宇鹏 《压电与声光》 CAS 北大核心 2023年第3期467-470,共4页
为了能够在复杂环境下实现风速风向的高精度和高稳定性测量,在基于声学共振原理的风传感器系统的基础上,采用闭环控制扫描技术改进了系统的性能指标。采用声学共振的方式,同时对换能器产生的信号进行频率调制和强度调制,实现对超声换能... 为了能够在复杂环境下实现风速风向的高精度和高稳定性测量,在基于声学共振原理的风传感器系统的基础上,采用闭环控制扫描技术改进了系统的性能指标。采用声学共振的方式,同时对换能器产生的信号进行频率调制和强度调制,实现对超声换能器的线型扫描。频率调制解决了在不同压力、温度等环境因素影响下导致的共振频移的问题,强度调制解决了换能器性能随时间衰减问题,极大地提高了信噪比。实验结果表明,采用闭环控制的方法可以准确测量风速风向。风速测量范围0~50 m/s,风速测量精度为±0.5 m/s(≤15m/s)/±5%(>15 m/s且<35 m/s)/±9%(>35 m/s)。改进后的系统在复杂环境下受环境变化影响小、精度高、稳定性好、抗干扰能力强。 展开更多
关键词 闭环控制 频率调制 线型扫描 共振频移 风速测量
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Evaluation of Normal Adrenal Gland Volume by 64-slice CT 被引量:4
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作者 Xuan Wang Zheng-yu Jin +4 位作者 Hua-dan Xue Wei Liu Hao Sun Yu Chen Kai Xu 《Chinese Medical Sciences Journal》 CAS CSCD 2012年第4期220-224,共5页
Objective To measure volume and other parameters of normal adrenal glands in Chinese adults with 64-slice multidetector CT, to evaluate the relationship of volume result with age, sex and body size, and to explore the... Objective To measure volume and other parameters of normal adrenal glands in Chinese adults with 64-slice multidetector CT, to evaluate the relationship of volume result with age, sex and body size, and to explore the correlations between adrenal volume and other measurements. Methods This study was based on 125 acquired contrast-enhanced upper abdominal CT scans performed with a 64-slice CT. The final study group consisted of 81 patients (49 males, 32 females). Portal venous phase images were studied for the measurements. Both the reconstruction interval and thickness were 1.5 mm. Each adrenal gland was outlined manually with computer-assistant technology to calculate its volume. The maximal sectional area, length, width and thickness of each adrenal gland were also measured. Results The mean age of total population was 47.9±13.0 (range: 20-76) years. The left, right, and total adrenal gland volumes were 4.23±0.74 (range: 2.85-5.83) cm 3 , 4.26±0.86 (2.59-6.56) cm 3 , and 8.50±1.40 (5.80-11.39) cm 3 , respectively. These volumes increased with weight (r=0.381, 0.389, and 0.437 respectively, all P<0.001), height (r=0.386, P<0.001; r=0.297, P=0.007; r=0.384, P<0.001) and body surface area (r=0.406, 0.392, and 0.452, all P<0.001). There was no significant difference in left, right or total adrenal volume with regard to sex after applying General Linear Model procedure to reduce the impact of weight (F=1.304, 0.064, and 0.597, all P>0.05), nor did volume change significantly with age (r=-0.033, -0.014, and -0.026, all P>0.05). Nearly all descriptors of bilateral adrenal glands correlated with ipsilateral volume except thickness (r=-0.027, P=0.814) and width (r=0.166, P=0.138) in the left side. Among these parameters, length had a stronger correlation with volume than others in the both left (r=0.412, P<0.001) and right (r=0.516, P<0.001) adrenal glands. Conclusion Our study has defined the volume distribution and other parameters of normal adrenal glands in Chinese adults, which provide a baseline for future studies. 展开更多
关键词 adrenal gland VOLUMETRY volume determination computed tomography
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Super-resolution amplification of bitmap images based on 3D modeling theory
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作者 ZHOU Lu-jie DANG Jian-wu WANG Yu-xin 《Journal of Measurement Science and Instrumentation》 CAS CSCD 2019年第4期335-341,共7页
As a general format of the image,bitmap(BMP)image has wide applications,and consequently it is an important part of image processing.By segmenting the bitmap and combining the three-dimesional(3D)model of the discrete... As a general format of the image,bitmap(BMP)image has wide applications,and consequently it is an important part of image processing.By segmenting the bitmap and combining the three-dimesional(3D)model of the discrete algorithm with the scanning line compensation algorithm,a mathematical model is built.According to the topological relations between several control points on the model surface,the surface of the model is discretized,and a planar triangle sequence is used to describe 3D objects.Finally,the bitmap is enlarged by combining the borrowing compensation based on 3D modeling principle of discrete algorithm with the scanning line compensation algorithm of binary lattice image,thus getting a relatively clear enlarged BMP image. 展开更多
关键词 image processing bitmap(BMP) image amplifying model three-dimensional(3D) modeling principle scanning line compensation algorithm
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三维激光点云扫描线曲率压缩算法研究 被引量:3
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作者 李海英 花向红 陈远 《测绘信息与工程》 2009年第5期43-45,共3页
提出了一种基于扫描曲线上各散乱点的曲率大小进行压缩的方法,实现了以曲线上各点的曲率大小为标准对扫描线数据进行精简压缩,试验数据取得了较好的压缩效果。
关键词 三维点云 数据压缩 扫描线型点云数据 曲率压缩算法
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Towards full repair of defects in reduced graphene oxide films by two-step graphitization 被引量:12
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作者 Ruben Rozada Juan I, Paredes Silvia Villar-Rodil Amelia Marlinez-Alonso Juan M. D. Tascon 《Nano Research》 SCIE EI CAS CSCD 2013年第3期216-233,共18页
The complete restoration of a perfect carbon lattice has been a central issue in the research on graphene derived from graphite oxide since this preparation route was first proposed several years ago, but such a goal ... The complete restoration of a perfect carbon lattice has been a central issue in the research on graphene derived from graphite oxide since this preparation route was first proposed several years ago, but such a goal has so far remained elusive. Here, we demonstrate that the highly defective structure of reduced graphene oxide sheets assembled into free-standing, paper-like films can be fully repaired by means of high temperature annealing (graphitization). Characterization of the films by X-ray photoelectron and Raman spectroscopy, X-ray diffraction and scanning tunneling microscopy indicated that the main stages in the transformation of the films were (i) complete removal of oxygen functional groups and generation of atomic vacancies (up to 1,500 ~C), and (ii) vacancy annihilation and coalescence of adjacent overlapping sheets to yield continuous polycrystalline layers (1,800-2,700 ~C) similar to those of highly oriented graphites. The prevailing type of defect in the polycrystalline layers were the grain boundaries separating neighboring domains, which were typically a few hundred nanometers in lateral size, exhibited long-range graphitic order and were virtually free of even atomic-sized defects. The electrical conductivity of the annealed films was as high as 577,000 S-m-1, which is by far the largest value reported to date for any material derived from graphene oxide, and strategies for further improvement without the need to resort to higher annealing temperatures are suggested. Overall, this work opens the prospect of truly achieving a complete restoration of the carbon lattice in graphene oxide materials. 展开更多
关键词 graphene graphene oxide FILMS ANNEALING defect
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