基于138平台的电能质量检测系统设计

现有的电能质量检测系统具有数据采集量和处理量大、实时性要求高等特点,并根据电力行业的发展现状,结合生产实际需求,提出了基于138平台+FPGA的分布式控制结构,以138平台为核心,充分发挥OMAPL-138平台DSP+ARM双核的优势,实现数据的高速率处理,通过FPGA实现通信协议的拓展,完成不同通信协议之间的转换,整体设计提高了系统的实时性和数据处理能力。该平台具有质量良好,稳定性好,具有一定的推广前景。     

Production of the Isomeric State of 138Cs in the Thermal Neutron Capture Reaction 137Cs(n, γ)138Cs

In order to obtain precise data of the neutron capture cross section of the reaction ¹³⁷Cs(n, γ)¹³⁸Cs, the production probability of isomer state ^138mCs was measured in this work. Targets of about 0.37MBq ¹³⁷Cs were irradiated for 3 min in. the pneumatic tube facility (Pn-3) of Kyoto University Reactor (KUR). The 1,436 keV gamma;-ray emitted from both of ^138gCs and ^138mCs was measured. A ratio of the production probability between ^138gCs and ^138mCs was deduced from time dependence of peak counts of 1,436 keV γ-ray by making use of difference of half-lives of ^138gCs (33.41 min) and ^138mCs (2.91 min). The production probability of ^138mCs was obtained as 0.75plusmn;0.18 and this value revised the effective cross section upwards by 9plusmn;2percnt;. The effective cross section ô and the thermal neutron capture cross section σo were obtained as ô=0.29±0.02 b and σ=0.27±0.03b with taking into account the production of ^138mCs.     

液晶滤色器用黄色颜料PY138的制备方法

液晶显示器用滤色片（CF）用三原色为红（R）、绿（G）以及蓝（B）。其中作为黄色用颜料,主要使用C．I．Pigment Yellow138,C．I．Pigment Yellow139以及C．I．PigmentYellow150。合成的粗品必须经过微细化以及稳定化的加工才可以作为液晶用有机颜料使用。     

Vector transport for shape-from-shading

In this paper we describe a new shape-from-shading method. We show how the parallel transport of surface normals can be used to impose curvature consistency and also to iteratively update surface normal directions so as to improve the brightness error. We commence by showing how to make local estimates of the Hessian matrix from surface normal information. With the local Hessian matrix to hand, we develop an “EM-like” algorithm for updating the surface normal directions. At each image location, parallel transport is applied to the neighbouring surface normals to generate a sample of local surface orientation predictions. From this sample, a local weighted estimate of the image brightness is made. The transported surface normal which gives the brightness prediction which is closest to this value is selected as the revised estimate of surface orientation. The revised surface normals obtained in this way may in turn be used to re-estimate the Hessian matrix, and the process iterated until stability is reached. We experiment with the method on a variety of real world and synthetic data. Here we explore the properties of the fields of surface normals and the height data delivered by the method.     

OMAP L138核间通信高吞吐量图像处理平台及应用

异构双核芯片 AMR+DSP具有强大的任务管理、人机交互和数据处理功能,为嵌入式图像处理领域提供了一种新的架构。为了减少开发人员对底层驱动的设计,TI 研发了 Syslink 驱动用于核间通信,包括 Notify、MessageQ 协议等,其中基于 MessageQ的通信协议常用于核间图像传输,但其占用资源较多、延迟高。本文对 TI 公司的达芬奇架构OMAP L138处理器的多核通信理论进行研究,利用核间中断寄存器和共享内存队列存储机制进行数据交互,实现了一种高吞吐量的图像处理平台。     

基于OMAPL138与FPGA的惯性姿态测量系统设计与实现

为了满足高性能、低成本及多接口的惯导使用需求,设计一种基于OMAPL138+FPGA的大存储空间惯性姿态测量系统;系统设计充分利用OMAPL138的异构双核结构,结合每种处理器应用特点,进行任务划分并构建硬件平台;设计了丰富的外围接口,通过选择接入GPS、北斗或里程计,能够实现多种组合导航方式;根据使用环境提出惯导与里程计组合导航方案和相应软件流程,并进行了姿态精度测量及导航定位精度试验;姿态测量精度优于0.5密位,纯惯性导航定位精度为0.3‰ D (CEP),组合导航的定位精度为0.14‰,试验结果表明,系统稳定可靠,硬件平台满足惯导计算机设计需求。     

OMAP—L138处理器的SD卡FAT文件系统读写

OMAP—L138在进行高速数字信号处理时通常会产生大量的数据。把这些数据存储在SD卡上不仅能降低在存储介质上的成本,而且还能加强数据的可移动性。FAT文件系统的引入则能更高效地管理SD卡上的数据。将FatFs模块移植到OMAP—L138平台上便能实现SD卡文件系统的读写功能。     

A comparison of design and model selection methods for supersaturated experiments

Various design and model selection methods are available for supersaturated designs having more factors than runs but little research is available on their comparison and evaluation. Simulated experiments are used to evaluate the use of E(s²)-optimal and Bayesian D-optimal designs and to compare three analysis strategies representing regression, shrinkage and a novel model-averaging procedure. Suggestions are made for choosing the values of the tuning constants for each approach. Findings include that (i) the preferred analysis is via shrinkage; (ii) designs with similar numbers of runs and factors can be effective for a considerable number of active effects of only moderate size; and (iii) unbalanced designs can perform well. Some comments are made on the performance of the design and analysis methods when effect sparsity does not hold.     

Neutron Resonance Parameters of Ba-135, Ba-137 and Ba-138

Neutron transmission measurements were carried out on the separated isotopes of Ba at the JAERI electron linac. Resonance energies and neutron widths were determined for a large number of resonances in the neutron energy range from 400 eV to 4.6 keV for ¹³⁵Ba, 15 keV for ¹³⁷Ba and 63 keV for ¹³⁸Ba. Many of these resonances were newly observed in this experiment. The s-wave strength functions obtained are S ₀= (1.33±0.22) x ^10-4 for ¹³⁵Ba, and S ₀= (0.51±0.12) x ^10-4 for ¹³⁷Ba. An apparent energy dependence of the strength function was observed for ¹³⁵Ba. New resonance parameters of ¹³⁸Ba were also obtained for several weak P-wave levels.     

基于OMAP-L138平台SPI总线的嵌入式应用

数据的采集和控制是嵌入式应用领域的重点课题,随着数字转模拟器件精度的扩展和转换速率的提升,需要更加高效的运算平台和方法。PCM1702是一款高达20位分辨率的精密数字模拟转换器,其还具备超低失真、低噪声和快速电流输出等特性。SPI总线接口是嵌入式Linux系统中的典型应用,在高性能达芬奇平台OMAP L138处理器ARM+DSP双核环境下,通过GPIO实现SPI总线驱动,在高精度DA芯片PCM1702控制中得到应用。实验结果表明该驱动实现方法高效、稳定,具备针对精密器件的高速处理能力。