摘要：对经皮肾造口取石术（PCNL）前的CT肾盂成像检查进行回顾性研究。对20例肾结石病人应用精心设计的方案进行CT肾盂成像。评分并比较横断位、冠状位最大密度投影（MIP）和容积再现（VR）影像上结石的大小、对比剂排泄的一致性及结石和肾盂肾盏系统重建的准确性。注射对比剂后,横断位像可准确显示结石大小,而在冠状位像上常被低估。增强前后测量结果分别平均为14．7mm：14．4mm（横断位）、17．2mm：16．1mm（冠状位）（P=0．11和0．03）。

摘要：Electronic throttle control (ETC) system has work.d its way to becoming a standard subsystem in most of the current automobiles as it has contributed much to the improvement of fuel economy, emissions, drivability and safety. Precision control of the subsystem, which consists of a dc motor driving a throttle plate, a pre-loaded return spring and a set of gear train to regulate airflow into the engine, seems rather straightforward and yet complex. The difficulties lie in the unk.own system parameters, hard nonlinearity of the pre-loaded spring that pulls the throttle plate to its default position, and friction, among others. In this paper, we extend our previous results obtained for the modeling, unk.own system parameters identification and control of a commercially available Bosch’s DV-E5 ETC system. Details of modeling and parameters identification based on laboratory experiments, data analysis, and k.owledge of the system are provided. The parameters identification results were verified and validated by a real-time PID control implemented with an xPC Target. A nonlinear control design was then proposed utilizing the input-output feedback.linearization approach and technique. In view of a recent massive auto recalls due to the controversial uncontrollable engine accelerations, the results of this paper may inspire further research interest on the drive-by-wire technology.