Wireless retrospective gating: Application to cine cardiac imaging

A new “wireless” method of cardiac imaging is introduced, which, unlike ECG triggering, allows imaging the heart at end-diastole, and greatly reduces smearing artifacts in the phase-encoding direction. It is an improvement over ECG-driven retrospective gating, in that patients with poor ECGs can be imaged. This method extends the applicability of cardiac imaging, and since it requires no physiological monitoring hardware, can be implemented easily on any MR imager. The images produced by this method are superior to those from ECG triggering, especially when viewed in a “cine” loop. The technique described herein is, furthermore, extendable to any area where periodic or quasi-periodic motion is a problem.     

Cerebral abnormalities in Wilson''s disease as evaluated by ultra-low-field magnetic resonance imaging and computerized image processing

The cerebral involvement of a 13-yr-old boy with Wilson's disease was serially evaluated during the first 18 mo of D-penicillamine treatment. An ultra-low-field magnetic resonance imaging (ULF MRI) system, operating at 0.02 T, with computerized image processing was used. The half-yr period prior to the clinical diagnosis was set, the patient had showed poor school performance, emotional lability, deteriorating handwriting, progressively slow, gross, and fine motor functions, and a fixed rigid smile. No overt signs of liver disease were found. With D-penicillamine treatment (1–1.5 g/d) a continuous improvement was seen. The pretreatment MRI investigation showed pronounced pathological transformation in the basal ganglia. However, changes were seen also in most other parts of the brain indicating diffuse involvement. During treatment the computerized MR images became gradually more normal. The current magnetic resonance imaging system with computerized image processing is a sensitive and simple method for evaluation of subtle parenchymal changes of the brain.     

一种激光扫描水下成像系统的衰减长度值研究

简述了水下目标激光成像方法和优点。并描述了一种水下连续蓝绿激光点扫描，微光增强ＣＣＤ面成像实验系统。分析了该系统的物理模型和计算公式。验证：处于对比度极限模式工作时。在水质及目标确定条件下，该值也许可成为判断系统优劣的依据。     

光CT的扇束投影重排方法及投影几何分析

在工业过程监控中,由于被测物理过程的发生时间短,因此光CT装置将不可能象医学CT那样有充足的时间进行"静态"成像,而是必须进行实时性较高的"动态"成像(或称为流动成像).其制约是光线扫描的投影视角和投影数量都不可能太多.根据这一情况,在医学CT中常用的一些图像重建算法如反投影法、滤波反投影法和投影重排方法都必须加以改进才能引用.为此,本文研究扇束投影重排方法在光学流动成像中的应用可行性,分析其计算方法和步骤,并确定光线扇束结构中的光源个数、扇形张角和探测器个数之间的约束关系,同时也分析了内插精度对图像质量的影响.在数值模拟实验中,将投影重排方法与反投影法的重建图象进行了比较,进一步评判本文方法的图象质量和成像实时性等方面的性能.     

基于图像特征的成像制导对抗干扰效果评估方法

文章基于图像特征引入了对比度评估和相关度评估干扰系数的概念,通过计算干扰系 数的大小可以定量评估干扰效果的好坏。这对于光电对抗装备的研制、开发和效能评估具有重要参考价值。     

Cover Picture: Preparation and Application of Novel Microspheres Possessing Autofluorescent Properties (Adv. Funct. Mater. 16/2007)

On p. 3153, Guang‐Hui Ma and co‐workers report on the development of autofluorescent chitosan microspheres with tunable color based on different crosslinking reagents and further chemical modification. The fluorescent intensity can also be controlled by the particle size and crosslinking degree. The autofluorescent microspheres may be useful in fluorescence assays as bright, inexpensive, and stable probes for qualitative and quantitative studies of biological interactions and drug delivery. Fluorescent microspheres are widely used as biological tracers. In this study, uniformly sized chitosan microspheres crosslinked with glutaraldehyde (CG microspheres) and formaldehyde (CF microspheres) are successfully prepared by the Shirasu Porous Glass (SPG) membrane emulsification technique. Selectively reduced CG microspheres (SRCG microspheres) are obtained by NaBH₄ reduction. These chitosan microspheres are found to exhibit fluorescent properties without conjugation to any fluorescent agent. The fluorescence color varies with different crosslinkers and can be modulated by further chemical reduction, whereas the fluorescence intensity can be controlled by tuning the particle size and degree of crosslinking. The autofluorescence of the microspheres is applied to study the phagocytosis of HepG2 cells using the microspheres as novel tracers. Quantitative and qualitative evaluations show that these chitosan microspheres serve as bright, inert, durable, and extremely photostable tracers.     

红外成象制导武器及其导引头的现状与发展

综述了红外成象导引头的发展与现状，介绍了几种典型的红外成象导引头及成象制导武器，分析了导引头中的技术关键，评述了红外成象导引头今后的发展趋势。     

水下激光成像及主要参数的理论计算

利用双流辐射理论，导出了信号光辐射照度的表达式。从理论上计算了同步扫描系统的信号光和后向散射光传到探测器的辐照度与衰减长度的定量关系。减小视场角和增大光源到探测器的距离可增成像距离。     

双光子技术在三维成像和三维存储技术中的应用

对双光子过程的空间分辨能力进行了理论分析。阐明了双光子技术在三维成像和三维存储中的独特优势。着重介绍了双光子技术与扫描共焦显微术、近场显微术相结合进行三维成像 ,以及一种多焦点多光子显微术和用连续光源激发的双光子三维成像技术的研究和进展情况。对建立在共焦显微镜基础之上的双光子三维光存储和微细加工方面的研究也作了回顾与展望     

机载SAR发展概况

机载SAR具有提供高分辨率成像的能力，这种能力不受气象条件和太阳照射的限制，因此得到了广泛应用。本文简要说明机载SAR的特点，主要介绍世界上一些机载SAR的现状、性能及主要参数。根据机载SAR发展过程及现状，讨论机载SAR的发展趋势。