基于流体动压润滑理论,考虑了磨削区流体为层流和湍流的流动状态,建立了浇注式供液方式下光滑表面间磨削区流体动压力的数学模型。在平面磨床上进行了流体动压力的实验研究,实验结果表明,当磨削区内流体的雷诺数小于300时,光滑表面间层...基于流体动压润滑理论,考虑了磨削区流体为层流和湍流的流动状态,建立了浇注式供液方式下光滑表面间磨削区流体动压力的数学模型。在平面磨床上进行了流体动压力的实验研究,实验结果表明,当磨削区内流体的雷诺数小于300时,光滑表面间层流状态的流体动压力模型可靠地预测了磨削区内流体的动压力;当300<Re<1500时,Ng and Pan的湍流模型理论值大于实验值,而Hirs的湍流模型的理论值与实验值较吻合;磨削区流体动压力随着砂轮速度的增加、最小间隙的减小而增大,最大压力峰值分布在砂轮工件最小间隙区域,且在该区域压力梯度变化明显。展开更多
Improvements in imaging technology allow exploitation of the dual blood supply of the liver to aid in the identif ication and characterisation of both malignant and benign liver lesions. Imaging techniques available i...Improvements in imaging technology allow exploitation of the dual blood supply of the liver to aid in the identif ication and characterisation of both malignant and benign liver lesions. Imaging techniques available include contrast enhanced ultrasound, computed tomography and magnetic resonance imaging. This review discusses the application of several imaging techniques in the diagnosis and staging of both hepatocellular carcinoma and cholangiocarcinoma and outlines certain characteristics of benign liver lesions. The advantages of each imaging technique are highlighted, while underscoring the potential pitfalls and limitations of each imaging modality.展开更多
文摘基于流体动压润滑理论,考虑了磨削区流体为层流和湍流的流动状态,建立了浇注式供液方式下光滑表面间磨削区流体动压力的数学模型。在平面磨床上进行了流体动压力的实验研究,实验结果表明,当磨削区内流体的雷诺数小于300时,光滑表面间层流状态的流体动压力模型可靠地预测了磨削区内流体的动压力;当300<Re<1500时,Ng and Pan的湍流模型理论值大于实验值,而Hirs的湍流模型的理论值与实验值较吻合;磨削区流体动压力随着砂轮速度的增加、最小间隙的减小而增大,最大压力峰值分布在砂轮工件最小间隙区域,且在该区域压力梯度变化明显。
基金Supported by SAK is supported by a grant from the Higher Education Funding Council for England (HEFCE)SDTR is funded by grants from the British Medical Research Council (MRC), London, UK+3 种基金the British Engineering, Physics and Science Research Council (EPSRC), Swindon, UKthe Alan Morement Memorial Fund AMMF, Essex, UKBroad Foundation, Los Angeles, USAPfizer Global Research and Development Inc, Sandwich, UK and GlaxoSmithKline, Ware, UK
文摘Improvements in imaging technology allow exploitation of the dual blood supply of the liver to aid in the identif ication and characterisation of both malignant and benign liver lesions. Imaging techniques available include contrast enhanced ultrasound, computed tomography and magnetic resonance imaging. This review discusses the application of several imaging techniques in the diagnosis and staging of both hepatocellular carcinoma and cholangiocarcinoma and outlines certain characteristics of benign liver lesions. The advantages of each imaging technique are highlighted, while underscoring the potential pitfalls and limitations of each imaging modality.
