共查询到20条相似文献,搜索用时 15 毫秒
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Shinji Tsuboi Nobufumi Atoda Yoshio Yamashita Kinya Ashikaga Isao Yamada Jiro Matsuo 《Microelectronic Engineering》1996,30(1-4):207-210
A viable method for the improvement of the polycrystalline diamond X-ray mask membrane is proposed. The use of an ionized cluster beam yields the smoothest surface. Sol-gel planarization film coating with indium tin oxide is the most effective method for obtaining high optical transmittance without sacrificing high synchrotron irradiation durability. 相似文献
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The scattering properties of low-Z high-density materials are discussed, through Monte Carlo simulation, in view of their utilization as membranes for X-ray masks. The interplay between low atomic number and high atomic density is discussed and a comparison with silicon is carried out, both in case of bulk targets and membranes. The low Z causes smaller proximity effects, but the decisive factor relative to silicon is constituted by the higher mechanical stiffness, which, in principle, allows to greatly reduce membrane thickness. However, we show that, in spite of the more favourable intrinsic scattering properties, the choice of these materials, in actual systems, is not always a real advantage. In the analysis of the single-layer resist process for X-ray mask fabrication, no significant difference relative to Si is found in the two limits of low and high energy. On the contrary, the choice of low-Z high-density materials is found to be advantageous at intermediate energy. In particular, we demonstrate that, while in the case of low-Z high-density materials, 0.15 μm resolution is successfully obtained already at 30 keV, in case of Si, this same resolution is only reached at e-beam energies of at least 40 keV. 相似文献
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基于四象限探测器的桥梁挠度实时监测系统研究 总被引:1,自引:1,他引:0
为了实现高精度的桥梁挠度测量,提出了一种基于四象限探测器的桥梁挠度实时监测方法和系统。四象限探测器能使系统在挠度测量的同时还能获得被测点的横向位移,实现二维测量,并且具有高频测量的能力。用本文方法和系统对桥梁挠度进行单点或多点测量,结果表明:测试单点纵向位移能达到20μm的分辨率,测试精度可达到0.1 mm。 相似文献
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激光图像挠度测量系统稳定性实验研究 总被引:2,自引:0,他引:2
本文介绍了适用于大型桥梁的激光图像挠度测量法的测量原理.在实验室构建出整个测量系统.并进行了室外和室内稳定性实验。实验结果表明该测量系统在室内具有较好的稳定性和可行性.能够用于具有密封梁体的大型刚构桥梁挠度的测量。 相似文献
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本设计应用单片机、步进电机驱动芯片、LED显示和键盘阵列,构建了集步进电机控制器和驱动器于一体的步进电机控制系统。讨论了一种步进电机变频调速的方法。本控制系统的开发采用了软硬件协同仿真的方法,有效地减少系统开发的周期和成本。 相似文献
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A method for prospective motion correction of X-ray imaging of the heart is presented. A 3D + t coronary model is reconstructed from a biplane coronary angiogram obtained during free breathing. The deformation field is parameterized by cardiac and respiratory phase, which enables the estimation of the state of the arteries at any phase of the cardiac-respiratory cycle. The motion of the three-dimensional (3-D) coronary model is projected onto the image planes and used to compute a dewarping function for motion correcting the images. The use of a 3-D coronary model facilitates motion correction of images acquired with the X-ray system at arbitrary orientations. The performance of the algorithm was measured by tracking the motion of selected left coronary landmarks using a template matching cross-correlation. In three patients, we motion corrected the same images used to construct their 3D + t coronary model. In this best case scenario, the algorithm reduced the motion of the landmarks by 84%-85%, from mean RMS displacements of 12.8-14.6 pixels to 2.1-2.2 pixels. Prospective motion correction was tested in five patients by building the coronary model from one dataset, and correcting a second dataset. The patient's cardiac and respiratory phase are monitored and used to calculate the appropriate correction parameters. The results showed a 48%-63% reduction in the motion of the landmarks, from a mean RMS displacement of 11.5-13.6 pixels to 4.4-7.1 pixels. 相似文献
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考虑到离轴三反系统内部结构和光路的复杂性,直接分析离轴三反系统内部各反射镜的偏转误差对视轴的影响难度较大。因此,提出一种将离轴三反系统模型简化为单反射系统模型来进行分析的方法,并在该模型的基础上建立离轴三反系统视轴偏转误差的计算公式。最后,利用Zemax软件创建离轴三反系统模型,通过变动反射镜位置来模拟系统视轴的变化,并得到成像点的坐标,再将得到的像点坐标代入计算公式求解出系统视轴的转动量。通过结果对比,求解出视轴的转动量相对于仿真的最大误差不超过4%,验证了基于单反射模型建立的理论分析方法的正确性。 相似文献
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《Philips Journal of Research》1998,51(2):231-251
This paper develops a Bayesian motion estimation algorithm for motion-compensated temporally recursive filtering of moving low-dose X-ray images (X-ray fluoroscopy). These images often exhibit a very low signal-to-noise ratio. The described motion estimation algorithm is made robust against noise by spatial and temporal regularization. A priori expectations about the spatial and temporal smoothness of the motion vector field are expressed by a generalized Gauss-Markov random field. The advantage of using a generalized Gauss-Markov random field is that, apart from smoothness, it also captures motion edges without requiring an edge detection threshold. The costs of edges are controlled by a single parameter, by means of which the influence of the regularization can be tuned from a median-filter-like behaviour to a linear-filter-like one. 相似文献
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在介绍模型编码基本原理的基础上,着重介绍了语义基编码,对它的运动估值技术作了详细分析,并用光流法对运动图像进行了运动估值,对该估值算法作了评价和展望。 相似文献
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本文设计了一种基于传感器和无线传输的运动辅助系统,人员佩戴的单元模块通过LoRa与上位机通信.接收上位机发出的心跳信号、采集运动和定位信息.肢体传感器通过2.4 G无线通信与相应的单元模块通信以及采集肢体运动数据.LoRa使得上位机可远程获取人员数据.单元模块和肢体传感器间采用2.4 G近距离通信,避免了各人员间数据干扰. 相似文献