科创中国

目的 应用三维斑点追踪显像技术研究慢性心力衰竭患者(CHF)左室扭转的运动特征,探讨其临床价值.方法 CHF组患者30例,年龄匹配的健康志愿者(对照组)33例,采集标准的四腔心及两腔心切面,进行全容积图像存储,应用3D-trace软件进行脱机分析,软件自动分析计算左心室舒张末期容积(LVEDV),左室收缩末期容积(LVESV),左室射血分数(LVEF),左室基底段收缩期扭转角度峰值(BTW),中间段收缩期扭转角度峰值(MTW),心尖段收缩期扭转角度峰值(ATW),左室整体收缩期扭转角度峰值(LVTW).结果 CHF组LVEF,LVTW,MTW,ATW均较正常组减低,BTW、MTW、ATW、LVTW与LVEF之间有明显的相关性,相关系数分别为0.557,0.926,0.932,0.945.结论 CHF患者左心收缩功能明显降低.三维斑点追踪技术为评估左心室的扭转运动提供了全新的工具,该方法具有广阔的应用前景.

Due to the large variations of environment with ever-changing background and vehicles with different shapes, colors and appearances, to implement a real-time on-board vehicle recognition system with high adaptability, efficiency and robustness in complicated environments, remains challenging. This paper introduces a simultaneous detection and tracking framework for robust on-board vehicle recognition based on monocular vision technology. The framework utilizes a novel layered machine learning and particle filter to build a multi-vehicle detection and tracking system. In the vehicle detection stage, a layered machine learning method is presented, which combines coarse-search and fine-search to obtain the target using the Ada Boost-based training algorithm. The pavement segmentation method based on characteristic similarity is proposed to estimate the most likely pavement area. Efficiency and accuracy are enhanced by restricting vehicle detection within the downsized area of pavement. In vehicle tracking stage, a multi-objective tracking algorithm based on target state management and particle filter is proposed. The proposed system is evaluated by roadway video captured in a variety of traffics, illumination, and weather conditions. The evaluating results show that, under conditions of proper illumination and clear vehicle appearance, the proposed system achieves 91.2% detection rate and 2.6% false detection rate. Experiments compared to typical algorithms show that, the presented algorithm reduces the false detection rate nearly by half at the cost of decreasing 2.7%–8.6% detection rate. This paper proposes a multi-vehicle detection and tracking system, which is promising for implementation in an on-board vehicle recognition system with high precision, strong robustness and low computational cost.

Friction compensation is particularly important for motion trajectory tracking control of pneumatic cylinders at low speed movement. However, most of the existing model-based friction compensation schemes use simple classical models, which are not enough to address applications with high-accuracy position requirements. Furthermore, the friction force in the cylinder is time-varying, and there exist rather severe unmodelled dynamics and unknown disturbances in the pneumatic system. To deal with these problems effectively, an adaptive robust controller with LuGre model-based dynamic friction compensation is constructed. The proposed controller employs on-line recursive least squares estimation(RLSE) to reduce the extent of parametric uncertainties, and utilizes the sliding mode control method to attenuate the effects of parameter estimation errors, unmodelled dynamics and disturbances. In addition, in order to realize LuGre model-based friction compensation, the modified dual-observer structure for estimating immeasurable friction internal state is developed. Therefore, a prescribed motion tracking transient performance and final tracking accuracy can be guaranteed. Since the system model uncertainties are unmatched, the recursive backstepping design technology is applied. In order to solve the conflicts between the sliding mode control design and the adaptive control design, the projection mapping is used to condition the RLSE algorithm so that the parameter estimates are kept within a known bounded convex set. Finally, the proposed controller is tested for tracking sinusoidal trajectories and smooth square trajectory under different loads and sudden disturbance. The testing results demonstrate that the achievable performance of the proposed controller is excellent and is much better than most other studies in literature. Especially when a 0.5 Hz sinusoidal trajectory is tracked, the maximum tracking error is 0.96 mm and the average tracking error is 0.45 mm. This paper constructs an adaptive robust controller which can compensate the friction force in the cylinder.

目的 探讨超声和CT在喉癌患者中甲状软骨受侵时诊断的准确性.方法 对80例正常对照组及87例喉癌可疑患者术前进行甲状软骨超声检查,与CT显示、手术结果进行对照分析.结果 超声对甲状软骨显示良好,本组74例喉癌患者甲状软骨受侵15例.在判断甲状软骨受侵时超声成像灵敏度要优于CT检查(P<0.05).结论 超声能够在喉癌患者中判断甲状软骨是否受侵及受侵情况,可为临床选择治疗方案、制定手术方式提供重要的依据.

目的 分析肝小静脉闭塞病的临床特点、影像表现和诊治经验.方法 回顾性分析2005年1月~2011年1月我院收治的5例肝小静脉闭塞病患者的临床资料.结果 根据临床及病理学资料,将肝小静脉闭塞病分为急性期(1例)、亚急性期(1例)和慢性期(3例).CT平扫检查均发现肝脏肿大,肝实质密度降低.彩色B超检查均发现肝静脉变细,血流变缓;4例患者存在腹水.行门-体分流术3例,其中好转2例,死亡1例.行内科保守治疗2例,其中1例治愈,1例好转.结论 肝小静脉闭塞病临床表现以肝脏肿大和腹水为特征.影像学检查对肝小静脉闭塞病诊断有重要价值.急性期患者宜采取内科保守治疗,若出现门脉高压症状时,应行门-体分流术治疗.

Three dimensional(3D)displacements,which can be translated further into 3D strain,are key parameters for design,manufacturing and quality control.Using different optical setups,phase-shift methods,and algorithms,several different 3D electronic speckle pattern interferometry(ESPI)systems for displacement and strain measurements have been achieved and commercialized.This paper provides a review of the recent developments in ESPI systems for 3D displacement and strain measurement.After an overview of the fundamentals of ESPI theory,temporal phase-shift,and spatial phase-shift techniques,3D deformation measurements by the temporal phase-shift ESPI system,which is suited well for static measurement,and by the spatial phase-shift ESPI system,which is particularly useful for dynamic measurement,are discussed.For each method,the basic theory,a brief derivation and different optical layouts are presented.The state of art application,potential and limitation of the ESPI systems are shown and demonstrated.

目的通过分析磁共振T1WI-SPIR序列半月板撕裂的征象并与关节镜结果对比以探讨其在半月板撕裂诊断中的临床应用价值.方法回顾性分析45例经关节镜证实的半月板撕裂病人T1WI-SPIR表现并与关节镜结果对比.结果45例90个半月板T1WI-SPIR诊断撕裂70个,关节镜证实50个,MR敏感性100%,准确率71%.结论磁共振T1WI-SPIR序列诊断半月板撕裂较为敏感,但存在一定假阳性.

目的 应用彩色多普勒超声观察吡格列酮对ApoE基因敲除小鼠(ApoE-/-小鼠)主动脉内-中膜厚度(intima-media thickness,IMT)、最大血流速度(Vmax)、阻力指数(residence index)的影响及其与小鼠血清脂联素水平的关系.方法 ApoE-/-小鼠30只,随机分成3个亚组:安慰剂组(n=10)、小剂量吡格列酮治疗组[10 mg/(kg· d),n=10]、大剂量吡格列酮治疗组[20mg/(kg·d),n=10].高脂饮食及不同剂量吡格列酮喂养28 d后,比较小鼠主动脉超声改变及血浆脂联素水平.以野生型C57BL/6J小鼠(n=9)做为对照组.结果 ApoE-/-小鼠动脉主动脉内膜可见硬化斑,对照组小鼠主动脉内膜未见硬化斑.高剂量组小鼠主动脉内膜硬化斑少于安慰剂组.安慰剂组小鼠主动脉内-中膜厚度( intima-media thickness,IMT)较对照组小鼠明显增加(P<0.01),大剂量组小鼠主动脉IMT低于安慰剂组和低剂量吡格列酮组小鼠的IMT (P<0.05).高剂量吡格列酮组小鼠主动脉最大血流速度较安慰剂组降低(P<0.05).各组主动脉阻力指数差异无统计学差异.大剂量吡格列酮组小鼠血浆脂联素水平高于安慰剂组及低剂量吡格列酮组小鼠(P<0.05).结论 采用具有高频探头的高档彩色多普勒超声诊断仪可清楚显示小鼠主动脉IMT.吡格列酮可以抑制动脉粥样硬化形成,该抑制作用与提高血浆脂联素水平相关.