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91.
Shingo Kato Kakuya Kitagawa Yeonyee E. Yoon Hiroshi Nakajima Motonori Nagata Shinichi Takase Shiro Nakamori Masaaki Ito Hajime Sakuma 《Magnetic resonance imaging》2014
Purpose
The purposes of this study were to evaluate the reproducibility for measuring the cold pressor test (CPT)-induced myocardial blood flow (MBF) alteration using phase-contrast (PC) cine MRI, and to determine if this approach could detect altered MBF response to CPT in smokers.Materials and methods
After obtaining informed consent, ten healthy male non-smokers (mean age: 28 ± 5 years) and ten age-matched male smokers (smoking duration ≥ 5 years, mean age: 28 ± 3 years) were examined in this institutional review board approved study. Breath-hold PC cine MR images of the coronary sinus were obtained with a 3 T MR imager with 32 channel coils at rest and during a CPT performed after immersing one foot in ice water. MBF was calculated as coronary sinus flow divided by the left ventricular (LV) mass which was given as a total LV myocardial volume measured on cine MRI multiplied by the specific gravity (1.05 g/mL).Results
In non-smokers, MBF was 0.86 ± 0.25 mL/min/g at rest, with a significant increase to 1.20 ± 0.36 mL/min/g seen during CPT (percentage change of MBF (?MBF (%)); 39.2% ± 14.4%, p < 0.001). Inter-study reproducibility for ?MBF (%) measurements by different MR technologist was good, as indicated by the intraclass correlation coefficient of 0.93 and reproducibility coefficient of 10.5%. There was no significant difference between smokers and non-smokers for resting MBF (0.85 ± 0.32 mL/min/g, p = 0.91). However, ?MBF (%) in smokers was significantly reduced (-4.0 ± 32.2% vs. 39.2 ± 14.4%, p = 0.011).Conclusion
PC cine MRI can be used to reproducibly quantify MBF response to CPT and to detect impaired flow response in smokers. This MR approach may be useful for monitoring the sequential change of coronary blood flow in various potentially pathologic conditions and for investigating its relationship with cardiovascular risk. 相似文献92.
As the increasing number of buses in multi-core SoC designs, bus planning problems become a dominant factor in determining the chip performance. To cope with these issues, it is desirable to consider them in the early floorplanning stage. Recently, many bus-driven floorplanners have been proposed in the literature. However, these proposed algorithms only consider the bus planning problem without the thermal effect. As a result, there are hotspots, which result in high chip temperature, on the chip. In this paper, a thermal-driven bus-driven floorplanning algorithm is proposed to separate hotspots during the perturbation stage and to keep buses away from hotspots during the routing stage. To avoid time-consuming thermal simulations, the superposition of thermal profiles, which are the thermal distribution of each module, is adopted to efficiently estimate the module temperature. Compared with the state-of-the-art bus-driven floorplanner, experimental results demonstrate that the proposed algorithm can effectively separate hotspots and reduce the chip temperature. 相似文献
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非均匀有理B样条(NURBS)是CAD设计中广泛使用的技术。本基于平面几何知识给出了三角形约束的圆与椭圆曲线的NURBS表示,为工程设计中使用这类曲线提供了可计算性。 相似文献
95.
介绍了模拟集成电路设计自动化工具的研究进展 ,详细叙述了有关模拟 IC设计自动化(DA)所用到的种种方法以及各种方法的优劣 ,提出了一些解决方案。介绍了模拟硬件描述语言(AHDLs)以及目前开发混合信号和混合层次 EDA的情况 ,最后叙述了所开发的基于知识的自动化器件产生器。器件产生器的设计思想有效地使用了电路模拟器和从它所得到的信息 ,且器件产生器自适应于工艺过程 ,因此既有基于模型设计系统的短设计时间 ,又有基于模拟设计系统的精确性 ,而且它提高了第一次投片成功率与设计周期之比。 相似文献
96.
文章介绍了一种标准单元版图综合工具(cell layout synthesis system),这是一种完全自动化的EDA工具,它能根据输入单元电路网表和设计规则及单元库高度等参数自动生成符合设计要求且满足设计规则的单元版图。系统采用了改进的布图模式,得出了面积和电性能更加优化的单元版图。文中介绍了系统的设计流程,分析了系统采用的核心布局布线算法,以及在算法实现过程中为适应单元版图的特点和提高效率 相似文献
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99.
钣金CAD/CAPP/CAM系统及其集成技术 总被引:2,自引:0,他引:2
结合我所钣金结构设计、工艺设计和加工现状以及在实施 CAD/CAPP/CAM工作中积累的一些经验 ,探讨了钣金零件 CAD/CAPP/CAM的系统组成、应用特点与集成技术。 相似文献
100.