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排序方式: 共有775条查询结果,搜索用时 31 毫秒
1.
Although High Resolution X-ray Micro Tomography (HRXMT) has been developed in the past years for the 3D analysis of multiphase mineral particles in packed particle beds, image analysis of fine and/or high-density/high atomic number particles has been limited by existing segmentation algorithms. In this regard, a feature-based segmentation algorithm has been developed and demonstrated to provide a more accurate image processing method for the analysis of such multiphase particle populations. Based on this improved segmentation algorithm, image analyses of packed particle bed samples were compared to segmentation by traditional 3D watershed segmentation. Also, calculation of particle number using optical microscopy, together with a digital camera, was accomplished to validate feature-based segmentation. Detailed procedures and results for sample preparation, image analysis and validation are presented and discussed. 相似文献
2.
Despite the popularity of the analogue measuring devices, there is no recognized reference provided comprehensive guidelines for determining their resolution and its associated uncertainty. For filling this gap, this article is introduced as an attempt to explore and investigate all the available works related to this issue. The new terminology “evident space”, “evident resolution”, and “conjunction” were proposed to set a common reference. Two different techniques for determining the analogue resolution were presented and discussed. Several numerical examples were also presented to show different analogue indications and their interpretations. Moreover, reasonable recommendations for determining the resolution uncertainty were suggested depending on the case. 相似文献
3.
LIU Liying ZHENG Feng ZHANG Guoyu XU Yigang Yang Liyan LV Wenhu BIAN Zeqiang CHONG Wei LI Ye 《国外电子测量技术》2017,4(1):24-31
A new generation of solar spectroradiometerhas been developed by CUST/JRSI to improve solarirradiance observation data underhyperspectral resolution. It is based on the grating spectroradiometer with a back-thinned CCD linear image sensor and is operated in a hermetically sealed enclosure. The solar spectroradiometer is designed to measure the solar spectral irradiance from 300nm to 1100nm wavelength range with the spectral resolution of 2nm (the full width at half maximum). The optical bench is optimized to minimize stray light. The Peltier device is used to stabilize the temperature of CCD sensor to 25℃, while the change of temperature of CCD sensor is controlled to ±1℃ by the dedicated Peltierdriver and control circuit. 相似文献
4.
在浙江省人多地少的环境下,农村宅基地供不应求,而相应的宅基地审批制度却存在问题。文章通过调查访谈,总结审批中出现的实际问题,结合制度经济学的相关理论,分析问题产生的原因并提出相应的解决策略,从而完善宅基地的审批程序,推进新型农村社区的发展。 相似文献
5.
对风云三号(FY-3)中分辨率光谱成像仪(MERSI)的黑体进行了在轨太阳污染模拟,以掌握在轨太阳污染对面源黑体的影响,同时研究了抑制太阳污染的措施。模拟了FY-3卫星轨道及全轨道周期内太阳光的入射角,使用Tracepro软件建立了太阳污染模拟的模型,利用太阳光入射与MERSI的相对位置对太阳污染进行仿真,分析了污染随光谱成像仪扫描镜旋转和卫星飞行位置的变化。最后,根据分析结果设计了太阳污染抑制措施,并对抑制效果进行了仿真验证。结果表明:在扫描镜附近区域设置遮光板,有效地抑制了太阳光的污染,使辐射量级小于0.1 W,整个太阳污染功率下降了97%以上,对黑体有良好的保护效果。另外,提出的方法提高了面源黑体温度的均匀性和稳定性,保证了红外通道星上定标精度。 相似文献
6.
分析研究了风云-3C中分辨率光谱成像仪(FY-3C/MERSI)发射一年以来反射太阳波段的辐射定标精度,利用位于全球范围内的沙漠、盐湖等12种亮度稳定目标,结合中分辨率成像光谱仪(MODIS)的地表和大气参数产品和大气辐射传输模型,计算出了卫星过境时刻入瞳处的波段反射率,并将其作为在轨绝对辐射定标精度检验的参考真值,对2014年1月~10月期间,FY-3C/MERSI反射太阳波段的辐射定标精度进行了验证分析。结果表明,FY-3C/MERSI大部分波段在高低端的定标精度大小不一致。有些波段明显呈现高端定标偏差大,低端定标偏差小的特点;有些波段呈现高、低端定标偏差大,中间低的特点。在仪器发射一年以来,波段1~4,9~11,15~16和波段19仍能保持5%的定标精度。各波段定标精度的时间变化表明:在整个研究时期内,除蓝光波段和水汽吸收波段,其他波段的定标精度变化幅度基本在5%以内。实验结果显示:使用沙漠及盐湖等多种亮度稳定目标,有效地掌握了更宽动态范围内FY-3C/MERSI的辐射定标精度情况。 相似文献
7.
《Measurement》2014
The temperature distribution as a function of time and space is reconstructed over a non-homogeneous media having an arbitrary three-dimensional geometry. This is done by applying an inverse problem to the collected data from optimally placed sensors on the boundary surface of the object under study. Sensor positioning and the choice of the number of sensors are optimized in terms of the resolution of the reconstructed temperature field and the error propagation of the method in case of uncertain measurements. The method can be performed in real time since the major computation burden is performed off-line. 相似文献
8.
中子三轴谱仪分辨率的计算与分析 总被引:1,自引:0,他引:1
描述了中子三轴谱仪分辨率函数的计算方法,计算分析了中子波矢、准直器水平发散度、谱仪布局及能量和动量转移对分辨率函数的影响.谱仪分辨率随着入射波矢增大而降低,随着准直器水平发散度的减小而提高,谱仪最高能量分辨率能达到23μeV,计算值与实验测量和模拟计算结果符合得很好;谱仪布局只改变分辨率椭球在散射平面的方向,而不会影响... 相似文献
9.
Aziza K. Genena Danielle B. Luiz Wilhelm Gebhardt Regina F.P.M. Moreira Humberto J. José 《臭氧:科学与工程》2011,33(4):308-328
The elimination of the pesticide imazalil (IMZ) spiked into ultrapure water as well as into wastewater applying ozone (O3) and the identification of transformation products was investigated. O3 under hydroxyl radical suppression conditions reacted rapidly with the aliphatic double bond or the imidazole ring in IMZ, yielding several transformation products by partial oxidation. The structures of four oxidation products not yet described were characterized and identified after liquid chromatography coupled with high resolution, high mass accuracy, mass and tandem mass spectrometry (LC/MS and -MSn) in ultrapure water. For two identified transformation products, generated via direct ozone attack on IMZ, formation pathways were proposed. In wastewater, only two of those transformation products were observed. Kinetics studies for the reaction of IMZ with O3, evaluated by the competition kinetic method, resulted in a second-order rate constant kO3,IMZ ~ (1.02 ± 0.03)?×?105 M?1 s?1 at pH 6.6 ± 0.2, indicating that IMZ is completely transformed during the ozonation process. Tests of acute toxicity were performed applying a solution of IMZ in ultrapure water or treated wastewater to Daphnia magna. In both cases the decrease of toxicity was observed after ozone treatment. 相似文献
10.