输电线路冰害事故统计分析及防治措施研究

针对近年来发生的由覆冰引起的倒塔断线、冰闪及舞动等冰害事故,对几种不同冰害事故分析了其形成过程及特点。并从自然气象条件和设计等方面分析了冰害事故发生的原因。结合冰害事故都是由覆冰引起这一特点,分析了覆冰的形成机理及影响覆冰的因素,从设计和运行维护上提出了防治冰害事故的措施。     

Unsupervised image segmentation using a simple MRF model with a new implementation scheme

A simple Markov random field model with a new implementation scheme is proposed for unsupervised image segmentation based on image features. The traditional two-component MRF model for segmentation requires training data to estimate necessary model parameters and is thus unsuitable for unsupervised segmentation. The new implementation scheme solves this problem by introducing a function-based weighting parameter between the two components. Using this method, the simple MRF model is able to automatically estimate model parameters and produce accurate unsupervised segmentation results. Experiments demonstrate that the proposed algorithm is able to segment various types of images (gray scale, color, texture) and achieves an improvement over the traditional method.     

人造滑冰场制冰技术及使用维护探讨

室内人造滑冰场是国内新兴的娱乐性体育活动场所，具有很大的开发潜力。介绍了冰场制冰原理、技术及冰面使用维护措施，并对两种不同的冰场制冰排管布置方式做了较为全面的比较分析。     

500kV神侯二回线冰闪简析

2003年3月11日500kV神侯二回线316号塔发生故障，结合当地的气候、故障点的位置、故障塔型式、绝缘配置及故障现象，对该次故障进行了综合分析，得出该次故障为冰闪故障的结论，并提出整改建议。     

Ice-Tank and Numerical Study of Frazil Ingestion by Submerged Intakes

This paper addresses the problem of frazil ingestion by submerged water intakes located offshore in frigid water. It is well known that intakes under such conditions are prone to blockage by frazil, small ice crystals that commonly occur when water, agitated by wind or current, supercools. However, little quantitative information exists delineating how intake shape and size influence intake ingestion of frazil ice. Presented herein are insights and quantitative trends associated with those influences. The insights and trends were obtained from observations of frazil in a set of unique ice-tank experiments of a common intake configuration. The experiments were extended through numerical simulation. The essential intake layout considered herein comprises a conical inlet connected by pipe to an onshore pump station, and fitted with an elevated cap. The study’s findings show how either a cap or larger intake-rim diameter reduce the rate of frazil ingestion. Reducing the rate of frazil ingestion may enable an intake to operate longer during periods of water supercooling, and thereby reduce the possibility of blockage by frazil.     

A technique for recording polycrystalline structure and orientation during in situ deformation cycles of rock analogues using an automated fabric analyser

Two in situ plane-strain deformation experiments on norcamphor and natural ice using synchronous recording of crystal c-axis orientations have been performed with an automated fabric analyser and a newly developed sample press and deformation stage. Without interrupting the deformation experiment, c-axis orientations are determined for each pixel in a 5 × 5 mm sample area at a spatial resolution of 5 μm/pixel. In the case of norcamphor, changes in microstructures and associated crystallographic information, at a strain rate of ～2 × 10(-5) s(-1), were recorded for the first time during a complete in situ deformation-cycle experiment that consisted of an annealing, deformation and post-deformation annealing path. In the case of natural ice, slower external strain rates (～1 × 10(-6) s(-1)) enabled the investigation of small changes in the polycrystal aggregate's crystallography and microstructure for small amounts of strain. The technical setup and first results from the experiments are presented.     

A comparative study of FMS tool allocation and part type selection approaches for a varying part type mix

Hankins and Rovito (1984) examined the impact of different tool policies on cutting tool inventory levels and spindle utilization for a flexible manufacturing system (FMS). This study provides a broader perspective of the impact of tool allocation approaches on flow times, tardiness, percent of orders tardy, machine utilization, and robot utilization. Part type selection procedures have been suggested for the FMS prerelease planning problem. However, very little research has specifically evaluated the part type selection procedures across different tool allocation approaches. Also, with the exception of Stecke and Kim (1988, 1991) no other known study has provided any insights on what tool allocation approaches are appropriate when processing different mixes of part types. This research is devoted to addressing those issues.Three tool allocation approaches, three production scheduling rules, and three levels of part mix are evaluated in this study through a similation model of a flexible manufacturing system. The specific impacts of the tool approaches, their interaction effects with the part type selection rules, and their effectiveness at different part type mix levels are provided through the use of a regression metamodel.     

攀枝花尾矿制备透水混凝土的实验研究

以攀枝花尾矿为原料制备透水混凝土,采用填充体积法进行配合比设计,通过投料法和插捣法进行透水混凝土的搅拌成型,考察了水灰比(W/C)、设计孔隙率等对试块性能的影响。结果表明,当设计孔隙率P为15%,水灰比为0.30时试块抗压强度达到最大值29.2 MPa,并且透水系数2 mm/s,能达到一般轻型抗压透水施工要求。     

光纤光栅冰力传感器的开发及应用

根据裸光纤光栅(FBG)对应变的灵敏度远高于对压力的灵敏度这一特点,设计了一种基于等强度梁结构的FBG冰力传感器,并可以通过调节封装构件的尺寸调节其测量压力的灵敏度系数。对传感器的标定结果显示,这种FBG冰力传感器的线性相关度良好,实测的灵敏度系数与理论值一致。该种传感器在冰激桥墩振动模型试验中得到了应用,成功监测了桥墩在不同冰速撞击下受到的冰力。实验表明,这种FBG传感器灵敏度高、可靠性好、对结构自身的影响很小,可直接测量冰的撞击力,适合于模型实验中的冰力监测。     

二元冰蓄冷系统中的纳米添加剂成核特性研究

为了获得蓄冰溶液中纳米成核添加剂的选择标准,选择在纯净水和乙二醇溶液两种不同的基体溶液中添加两类不同的纳米微粒（SiO₂和α-Al₂O₃）进行实验,观察得到了不同的成核效果.以相关润湿机理为基础,对实验结果进行初步分析后表明:不同质量分数的添加剂具有不同的成核效果;当纳米微粒添加到乙二醇溶液中时,由于两者润湿效果较差,从而导致微粒成核效果下降,混合溶液过冷解除温度下降,增加制冰能耗,因此添加剂颗粒与基体溶液的润湿性将严重影响其结冰成核效果,润湿性能越好,成核效果越好．