An augmented reality system for patient-specific guidance of cardiac catheter ablation procedures

We present a system to assist in the treatment of cardiac arrhythmias by catheter ablation. A patient-specific three-dimensional (3-D) anatomical model, constructed from magnetic resonance images, is merged with fluoroscopic images in an augmented reality environment that enables the transfer of electrocardiography (ECG) measurements and cardiac activation times onto the model. Accurate mapping is realized through the combination of: a new calibration technique, adapted to catheter guided treatments; a visual matching registration technique, allowing the electrophysiologist to align the model with contrast-enhanced images; and the use of virtual catheters, which enable the annotation of multiple ECG measurements on the model. These annotations can be visualized by color coding on the patient model. We provide an accuracy analysis of each of these components independently. Based on simulation and experiments, we determined a segmentation error of 0.6 mm, a calibration error in the order of 1 mm and a target registration error of 1.04 +/- 0.45 mm. The system provides a 3-D visualization of the cardiac activation pattern which may facilitate and improve diagnosis and treatment of the arrhytmia. Because of its low cost and similar advantages we believe our approach can compete with existing commercial solutions, which rely on dedicated hardware and costly catheters. We provide qualitative results of the first clinical use of the system in 11 ablation procedures.     

磁控溅射法生长CeO2/Si薄膜及其发光性质

利用反应磁控溅射法对CeO2薄膜的生长规律进行了研究.通过实验发现,溅射时氧气和氩气的比例对薄膜的成分和晶体质量有很大影响.在室温下测试了CeO2薄膜的PL谱,结果表明CeO2薄膜的发光主要来自于氧缺陷.     

Establishment of a knee-joint coordinate system from helical axes analysis--a kinematic approach without anatomical referencing

This study establishes a functional knee-joint coordinate system (FCS) derived from active motion. The scale invariant properties of helical axes were used in order to avoid inter-observer errors associated with the traditional anatomical referencing techniques. The algorithm was tested with six cadaveric specimens in a knee-joint motion and loading apparatus. To determine the FCS sensitivity to variable loading, rotational moments were applied to the tibia while extending and flexing the knee. Each derived FCS was compared with the clinically derived anatomical coordinate system (ACS). The FCS was reproducible when the loading condition was the same. Changing the rotational moments from internal to external affected the orientations and the positions of the FCS. The largest displacement of 20.8 mm in average occurred in the medio/lateral direction. The FCS corresponded with the ACS for all specimens and loading conditions. The origin was always located within the femur along the transepicondylar line. The orientations differed less than 16.6 degrees in average, thus allowing the use of clinical terminology. These findings suggest that the FCS might improve the ability to clinically assess kinematic alterations provided that the reference motion is reproducible.     

基站越区覆盖的控制

对基站越区覆盖对移动通信网络的影响进行了分析,研究了如何通过各种工具来分析评估基站的越区覆盖,并提出控制基站越区覆盖的方法.     

H.264编码器中1/4像素精度插值算法的VLSI实现

H.264视频编码标准中引入了1/4像素精度插值算法,大大提高了压缩效率,但同时使运算复杂度增加、存储带宽增大。针对以上问题,从运动估计的角度出发,采用一步插值法和数据复用技术,可使带宽减少26%,处理周期可减少45%;设计了相应的硬件结构:采用了5级流水线实现一步插值算法,通过输入缓冲单元实现了参考数据的复用;针对插值过程中产生的大量数据,采用乒乓操作结构,保证数据及时传递。该结构可以显著降低带宽,提高吞吐率,完全可以应用于实时编码器中。     

用XPS法研究SiO_2/4H-SiC界面的组成

利用X射线光电子谱(XPS)研究了高温氧化形成的SiO2/4H-SiC界面的化学组成.获取低浓度HF酸刻蚀速度基础上制备出超薄氧化膜(1～1.5 nm)样品,并借助标准物对照法辅助谱峰分析.结果表明,高温氧化SiO2/4H-SiC界面,类石墨碳较多,除Si1 成分外,还存在Si2 和Si3 两种低值氧化物.三种工艺处理后界面成分含量的对比,指出界面成分可通过合理工艺有效控制,以C-V测试曲线印证了界面成分减少对电学特性的改善.     

“一波三折”的“灵巧”迫弹

正美国是开展120毫米制导迫击炮弹研制工作最多的国家。早在20世纪80年代末,美国陆军就启动了120毫米光纤制导迫击炮弹(FOMP)项目,由波音公司负责演示验证制导光纤是否能够承受迫击炮发射时的高过载。1994年,波音公司开始为陆军生产少量FOMP制导迫击炮弹,供试验使用。但随后,这个项目的进展情况就鲜见报道。《简氏防务周刊》消息称,该项目有可能已被终止,因为FOMP制导迫击炮弹的射程不够远,而且采用电视导引头,不具有自主攻击能力。为满足迫击炮部队对精确打击能力的需求,美国陆军随后     

弹道修正火箭的捷联惯姿算法比较研究

针对灵巧弹药的特殊运动规律,对采用高精度惯姿算法改善弹道修正引信姿态探测精度进行探讨和研究。采用一种精确积分角增量的方法,对传统等效旋转矢量算法进行了修正,通过仿真验证了算法的性能,结果表明修正算法的精度具有一定的优势,为基于MEMS速率陀螺的弹载全姿态探测模块的工程化研究提出有益的建议。     

反辐射导弹破片毁伤地面目标仿真方法

针对地面复杂电子装备易遭受破片毁伤这一特点,且为有效解决复杂装备战场抢修研究战场损伤数据缺乏的问题,基于现有研究成果,完善了地面目标破片损伤概率模型,提出了地面复杂电子装备几何模型描述方法、战斗部起爆规律、战斗部破片仿真方法及目标损伤仿真方法,并开发了某型装备损伤仿真平台,验证了破片毁伤地面目标仿真方法有效性,研究成果将为破片毁伤研究及地面装备战损研究提供支撑。     

“电子讲解员”

“电子讲解员”是用在展览馆内进行自动讲解的设备。当观众前来参观时。这种设备便自动向观众介绍展览品的情况,介绍完毕又自动停止,并等待下一次再有观众时重复工作。