磁共振图像的重建、后处理及可视化是磁共振成像(MRI)系统的重要组成部分.本文开发了一个新的用于磁共振图像重建、后处理及可视化的开源框架YAP(Yet Another Pipeline),利用此框架可以方便地构建图像处理流水线.与现有的一些其他开源框架相比,本文开发的框架具有如下特点:(1)采用基于接口的设计,可使用基于接口的插件对流水线的功能进行扩展;(2)允许用户使用编写脚本的方式构建图像处理流水线,编辑与修改流水线都很方便;(3)支持带有分支结构的流水线,便于流水线的构建与调试.目前,该框架已经在商用系统中获得了应用. 相似文献
In this paper, a reconstruction problem of the spatial dependent acoustic source from multiple frequency data is discussed. Suppose that the source function is supported on a bounded domain and the piecewise constant intensities of the source are known on the support. We characterize unknown domain by the level set technique. And the level set function can be modeled by a Hamilton-Jacobi system. We use the ensemble Kalman filter approach to analyze the system state. This method can avoid to deal with the nonlinearity directly and reduce the computation complexity. In addition, the algorithm can achieve the stable state quickly with the Hamilton-Jacobi system. From some numerical examples, we show these advantages and verify the feasibility and effectiveness. 相似文献
Polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) were analysed in 95 mountainous and park soil samples collected from 19 sites in Beijing, China. The levels of PCDD/Fs in the mountainous soils were low (0.086–0.59; mean 0.29; median 0.23 ng I-TEQ/kg). The levels in the park soils far from the city centre were a little higher (0.39–0.88, mean0.68; median 0.75 ng I-TEQ/kg). However, in the park soils near to the city centre, there were an abrupt jump in their concentration (1.7–3.2; mean 2.3, median 1.7 ng I-TEQ/kg), about ten times higher than those in the mountainous sites. Comparison of PCDD/Fs homologues and congener compositions between possible sources and samples indicated that the mountainous and park soils in Beijing had been slightly contaminated mainly by sodium pentachlorophenate, sewage sludge, atmospheric deposition and vehicle exhaust. These results have also been supported by the principal component analysis. 相似文献
A mixture of bismuth nitrate pentahydrate and potassium aryltrifluoroborate in toluene under microwave heating at 120 °C for 20 min provides an interesting and mild reaction protocol for the synthesis of aryl nitrite. The conversion to aryl nitrites from aryltrifluoroborates without transition metal catalyst and base in high yields is remarkable. 相似文献
The broadband enhancement of single‑photon emission from nitrogen‐vacancy centers in nanodiamonds coupled to a planar multilayer metamaterial with hyperbolic dispersion is studied experimentally. The metamaterial is fabricated as an epitaxial metal/dielectric superlattice consisting of CMOS‐compatible ceramics: titanium nitride (TiN) and aluminum scandium nitride (AlxSc1‐xN). It is demonstrated that employing the metamaterial results in significant enhancement of collected single‑photon emission and reduction of the excited‐state lifetime. Our results could have an impact on future CMOS‐compatible integrated quantum sources.