井眼轨迹曲线的计算机描绘

阐述一种井眼轨迹的描绘方法即柱面图描绘法。这种方法可使测井人员更加直观、有效地根据测井资源（井斜角、方位角及测量井深）描绘井眼轨迹曲线。井眼坐标的计算方法采用平均角法,该方法计算简单、准确度高。柱面图描绘方法应用于测斜仪数据处理软件,可在计算机屏幕上获得井眼轨迹的水平投影图和垂直剖面图,为钻井工程技术人员合理地设计井下钻具结构,为定向井的设计和施工提供依据。实验结果表明,井眼轨迹柱面图描绘方法简单     

基于扩频载波技术的线缆调制解调器

介绍低压电网的信道模型 ,提出一种基于扩频载波技术的线缆调制解调器的设计思想及其构成。     

用PSD构成全方位高准确度数字水平仪

本文利用连续型光电位置探测器ＰＳＤ（Ｐｏｓｉｔｉｏｎ Ｓｅｎｓｉｔｉｖｅ Ｄｅｔｅｃｔｏｒ）作为传感器,以重力方向作为竖直基准,构成了一种全方位高准确度水平仪,能实时地给出待测平面的倾斜角度和倾斜方位,具有量程可调结构紧凑、应用范围广等特点。     

陆上风电扩展基础温度场分析

扩展基础是一种基本的重力式基础,经常使用在陆上风电工程中,是一种大体积混凝土基础,水化热对基础的影响不能忽略。本文运用有限元软件ABAQUS分析了混凝土浇筑后前7d扩展基础的温度场分布、温度发展规律、基础顶面和顶面温差等参数。计算结果表明:随着龄期的增长,基础底部的温度越来越高,顶部的温度略微下降;温度梯度和温度增量都满足规范要求。     

大型油罐破裂泄漏特征研究

统计了多起油罐破裂事故,并对油罐破裂特征及油品泄漏流场进行分析。通过事故案例统计,总结了三种典型的油罐破裂形式,得到了油罐易发生破裂的位置及原因。对事故案例后果进行分析,将油罐破裂泄漏过程分为两个阶段,并分别对其流场特性进行研究。以平板流动临界雷诺数为判定准则,对油库常见油品泄漏流动雷诺数进行计算,得出泄漏油品的流态绝大多数为完全发展的湍流。     

潜没式三角翼体对闸后突扩水跃的影响

针对泄水闸少数孔开启时,下游渠道形成主流受压缩的三元突扩水跃问题,建立1∶100的水工试验模型,并采用潜没式三角翼体作为辅助消能工控导水流,分析多种工况条件下跃前断面的水流流态。试验结果表明,潜没式三角翼体通过减小主流的单宽流量,重新调整了跃前断面动量与水位的分布,提高了跃前断面水流的整体稳定性,并缩短了泄水口至跃首断面间急流段的长度,改善了下游水流的衔接消能,效果良好。研究成果可为实际工程应用提供技术支持。     

A small-world network model for the simulation of fire spread onboard naval vessels

This work is devoted to the development of a small-world network model to predict real-time fire spread onboard naval vessels. This model takes into account short-range and long-range connections between neighboring and remote network compartments. Fire ignition and flashover, as well as fire transmissions through the walls and ventilation ducts are simulated using time-dependent normal probability density functions. Mean durations of fire transmission through the walls and ducts are determined by a three-zone model and a one-dimensional CFD code, respectively. Specific experiments are conducted in a steel room, representative of a naval vessel compartment, in order to validate the zone model. Then a proof of concept is developed by applying the network model to a full-scale vessel mockup composed of 113 compartments on 7 decks. A statistical study is conducted to produce fire risk maps, classifying the vessel compartments according to their propensity to burn.     

Performance analysis of coded space‐time adaptive detection in DS/CDMA systems over Rayleigh fading channels

In this paper, we study the use of channel coding in a direct‐sequence code‐division multiple‐access (DS‐CDMA) system that employs space‐time adaptive minimum‐mean square‐error (MMSE) interference suppression over Rayleigh fading channels. It is shown that the employment of adaptive antenna arrays at the receiver can assist in attenuating multiuser interference and at the same time speeds‐up the convergence rate of the adaptive receiver. In this work, we assess the accuracy of the theoretical results developed for the uncoded and convolutionally coded space‐time multiuser detector when applied to the adaptive case. It is found that the use of antenna arrays brings the receiver performance very close to its multiuser counterpart. Using performance error bounds, we show that a user‐capacity gain of approximately 200% can easily be achieved for the space‐time adaptive detector when used with a rate 1/2 convolutional code (CC) and a practical channel interleaver. This capacity gain is only 10% less than the gain achieved for the more complicated multiuser‐based receiver. Finally, we perform a comparison between convolutional and turbo coding where we find that the latter outperforms the former at all practical bit‐error rates (BER). Copyright © 2006 John Wiley & Sons, Ltd.     

基于频谱边缘检测的运动模糊方向精确估计

针对运动模糊图像的模糊方向估计问题,详细分析了匀速直线运动模糊图像的退化模型,提出一种在频域精确估计运动模糊方向的方法。首先,计算退化图像的频谱,用高斯-拉普拉斯(LoG)边缘检测算子检测出频谱中的暗条纹轮廓;然后,用Radon变换找出垂直于暗条纹的角度;最后,根据图像长宽比确定频谱暗条纹和模糊方向之间的关系,计算出模糊方向。仿真结果表明,对模糊尺度从7到30像素的退化图像的模糊方向估计误差不超过1°,估计结果非常精确。     

假定方位角法在缸沟煤矿的应用

针对缸沟煤矿井下巷道变形较快,测量控制点不易保存特点,提出了假定方位角法,并在巷道施工开口标定中得到了应用,经实践证实该法是科学的、实用的,有一定的借鉴价值。