综合性油藏描述：超越旅行时层析X射线成象法

１９９２年，Ａｍｏｃｏ石油开采公司、Ｃｏｎｏｃｏ有限公司、斯仑贝谢勘探开发公司和斯坦福大学合作，进行了油藏地球物理研究项目，旨在描述北Ｃｏｗｄｅｎ油田的西得克萨斯ＣＯ２先导试验中Ｇｒａｙｂｕｒｇ组的油藏特征变量。本项目的目的是通过超越旅行时层析Ｘ射线成角法描述油藏的非均质性及流动各向异性。本项目包括一系列综合测量工作，即：旅行时层析Ｘ射线成象、反射物成象、分析油藏连续槽波、研究用于裸眼井应力曲线估     

Morse set classification and hierarchical refinement using Conley index

Morse decomposition provides a numerically stable topological representation of vector fields that is crucial for their rigorous interpretation. However, Morse decomposition is not unique, and its granularity directly impacts its computational cost. In this paper, we propose an automatic refinement scheme to construct the Morse Connection Graph (MCG) of a given vector field in a hierarchical fashion. Our framework allows a Morse set to be refined through a local update of the flow combinatorialization graph, as well as the connection regions between Morse sets. The computation is fast because the most expensive computation is concentrated on a small portion of the domain. Furthermore, the present work allows the generation of a topologically consistent hierarchy of MCGs, which cannot be obtained using a global method. The classification of the extracted Morse sets is a crucial step for the construction of the MCG, for which the Poincare′ index is inadequate. We make use of an upper bound for the Conley index, provided by the Betti numbers of an index pair for a translation along the flow, to classify the Morse sets. This upper bound is sufficiently accurate for Morse set classification and provides supportive information for the automatic refinement process. An improved visualization technique for MCG is developed to incorporate the Conley indices. Finally, we apply the proposed techniques to a number of synthetic and realworld simulation data to demonstrate their utility.     

A method for quantitative display of three-dimensional regional myocardial function

The DSR (dynamic spatial reconstructor), a multiple X-ray source scanner that generates stop action three-dimensional (3-D) images of a cylindrical volume, was used for quantitative imaging of left ventricular 3-D wall geometry and function in experimentally induced canine left ventricular myocardial infarction. Impaired regional myocardial function was induced by myocardial ischemia or infarction in four mongrel dogs by closed-chest occlusion of the proximal left anterior descending (LAD) coronary artery. At intervals of 6-14 weeks post occlusion, the dogs were scanned with the DSR during biatrial contrast injection. The 3-D shape, extent, and function of hypokinetic myocardium was measured from the DSR images utilizing measurement of the rate of local systolic wall thickening to detect regions of normal, ischemic, or scarred myocardium. The results were compared to scar size and anatomic distribution measured at postmortem examination. The anatomic extent and relationship of hypocontractile to normally contracting muscle was visualized by computer generated, pseudo 3-D shaded surface displays of the left ventricular chamber and by topographic projections of regional wall thickening rates onto a map of the left ventricular endocardial surface. The location of myocardial infarction and the surrounding zone of impaired function is clearly defined by this 3-D CT scanning procedure. The display method presented here provides both localization and quantification of the volume of ischemic and infarcted myocardium.     

Impact of dietary n−3 FA deficiency on rat bone tissue FA composition

The effect of dietary n−3 FA deficiency on bone tissue FA composition was evaluated in growing rats. Two mixtures combining hydrogenated coconut oil with safflower oil served as the n−3-deficient dietary treatments and provided two levels of linoleic acid (LA). The n−3 treatments were formulated with added α-linolenic acid (LNA) from flaxseed oil (diet LNA) or LNA plus DHA, and both were balanced for LA. This study showed that bone is sensitive to changes in dietary n−3 FA and that DHA is more effective than LNA in maintaining DHA levels in these tissues.     

Incidence of different pork quality categories in a Portuguese slaughterhouse: A survey

This study was designed to evaluate the incidence of the PSE/DFD status in a Portuguese pig slaughterhouse, covering two seasons of the year (spring and summer) in order to find out if the proportions of those poor meat quality categories were sufficient to concern the meat industry. Meat quality classification was based on the measurements of the pH(60), pH(24), drip losses and colour (L, a, b) in the longissimus dorsi muscle (between the last third and fourth ribs) of 380 pigs randomly chosen from the line. The high global incidence of PSE and likely PSE (30%) as well as DFD (10%) carcasses and the enormous variation of the meat quality between the different days of analysis proves that the pig population presents a great variation of halothane genotype and that handling procedures have to be optimized in order to decrease stress and glycogen store depletion. The percentage of PSE carcasses during the summer season was double that found in the spring, probably due to a higher environmental temperature and relative humidity.     

An evaluation of the algorithms for determining local cerebral metabolic rates of glucose using positron emission tomography dynamic data

Measurement of the local cerebral metabolic rate of glucose (LCMRGlc) and the individual rate constant parameters of the [(18 )F]2-fluoro-2-deoxy-D-glucose (FDG) model can provide a clearer understanding and insight to the physiological processes in the human brain, and a quicker and more accurate means of diagnosis in clinical applications. A systematic study using simulated and clinical tissue time activity data is presented to evaluate several existing and newly developed major algorithms used for determining LCMRGlc and the individual rate constants from positron emission tomography dynamic data. The computational and statistical properties of the autoradiographic approach, weighted and unweighted nonlinear least squares methods, Patlak graphic approach, weighted integration method, linear least squares and generalized linear least squares methods are investigated and discussed in this paper.     

IEEE802.11ax基于时延敏感的上行链路自适应帧聚合传输方案

帧聚合传输技术因其高效的传输效率被广泛使用.针对密集部署环境,下一代无线局域网标准IEEE 802.11ax基于帧聚合传输技术提出多流量标识符技术,允许多种不同流量类型的数据聚合传输,提升了密集环境下帧聚合传输性能.然而,上行链路多用户随机接入机制无法保障诸如视频、语音等高吞吐率低时延的传输业务需求.因此,本文利用帧聚合多流量标识符技术,对密集部署站点流量随机到达过程建模分析,推导出帧聚合时延表达式,并提出自适应时延敏感帧聚合传输方案.该方案根据站点缓存数据包的时延约束,使用二分搜索算法动态地调整帧聚合数目来最大化网络整体吞吐率.仿真结果表明,所提方案能够有效地降低站点时延和丢包率,提升网络吞吐率.     

Laser-speckle angular-displacement sensor: theoretical and experimental study

A novel, to our knowledge, method for the measurement of angular displacement for arbitrarily shaped objects is presented in which the angular displacement is perpendicular to the optical axis. The method is based on Fourier-transforming the scattered field from a single laser beam that illuminates the target. The angular distribution of the light field at the target is linearly mapped on a linear image sensor placed in the Fourier plane. Measuring this displacement facilitates the determination of the angular displacement of the target. It is demonstrated both theoretically and experimentally that the angular-displacement sensor is insensitive to object shape and target distance if the linear image sensor is placed in the Fourier plane. A straightforward procedure for positioning the image sensor in the Fourier plane is presented. Any transverse or longitudinal movement of the target will give rise to partial speckle decorrelation, but it will not affect the angular measurement. Furthermore, any change in the illuminating wavelength will not affect the angular measurements. Theoretically and experimentally it is shown that the method has a resolution of 0.3 mdeg ( approximately 5 murad) for small angular displacements, and methods for further improvement in resolution is discussed. No special surface treatment is required for surfaces giving rise to fully developed speckle. The effect of partially developed speckle is considered both theoretically and experimentally.