可控的高度规整三角网格生成算法

本文提出了一种新的用户可控的高度规整三角网格生成算法.通过在网格表面上构造3个标量场,利用其等值线相交生成高度规整的三角网格.算法借助N-对称方向场来指导生成网格的边方向,在网格表面指定密度场来控制采样密度,同时还提供了特征对齐和对带边界模型的处理能力.所有的控制需求都被纳入标量场求解框架中统一优化.实验表明,本文的方法能够满足多种用户控制需求,生成高度规整的三角网格.     

高分辨率遥感在非煤矿山安全生产监测中的应用

近年,随着国产高分系列卫星的陆续成功发射以及无人机技术的井喷式发展,我国民用高分辨率遥感应用门槛趋于普适化、大众化,但鲜有在安全生产监测领域的应用研究。在非煤矿山严峻的安全形势下,本文引用国产卫星遥感和无人机航测等高分辨率遥感技术对非煤矿山实施安全监测应用分析和适用性评价。研究结果表明：高分辨率遥感技术能在矿山地表危险源隐患识别、安全生产红线规划、安全核心指标监测、设计参数复核以及威胁对象分析等危险源安全管控工作方面发挥显著性作用,能有效弥补矿山监控盲点、提高安全监管效率,能为矿山企业和当地政府安全运营和监管矿山生产活动提供合理的决策支撑和执法依据,并具有良好的推广运用价值。     

基于文本块密度和标签路径覆盖率的网页正文抽取

针对大多数网页除了正文信息外,还包括导航、广告和免责声明等噪声信息的问题。为了提高网页正文抽取的准确性,提出了一种基于文本块密度和标签路径覆盖率的抽取方法（CETD-TPC）,结合网页文本块密度特征和标签路径特征的优点,设计了融合两种特征的新特征,利用新特征抽取网页中的最佳文本块,最后,抽取该文本块中的正文内容。该方法有效地解决了网页正文中噪声块信息过滤和短文本难以抽取的问题,且无需训练和人工处理。在CleanEval数据集和从知名网站上随机选取的新闻网页数据集上的实验结果表明,CETD-TPC方法在不同数据源上均具有很好的适用性,抽取性能优于CETR、CETD和CEPR等算法。     

Preparation and performance evaluation of Er2O3 coating-type selective emitter

An Er2O3coating-type selective emitter for themophotovoltaic application was prepared by plasma spray technology.The test results show that plasma spray technology could be used to prepare the Er2O3coating-type selective emitter with good stability at 1400°C.Based on the measurements of the high temperature normal spectral emissivity and the spectral hemispherical emissivity of the samples at room temperature,the influence of the coating thickness was discussed,and the selective emission performance of the sample was evaluated using radiative efficiency as the criterion.The results demonstrate that the emission of substrate could not be neglected unless the coating thickness would be larger than the penetration depth,which is around100μm.The selective emission peak of the Er2O3coating occurs at 1550 nm,matching well with the GaSb cells.However,the radiative efficiency is not larger than that of the SiC emitter,because the non-convertible emission of 1.725–5 m accounts for a large proportion of the total radiation power,especially at high temperature.Effective suppression of this band emission is essential to the improvement of the radiation efficiency of the emitter.     

Real-time ray casting rendering of volume clipping in medical visualization

This paper presents a real-time ray casting rendering algorithm for “volume clipping plane“ as an extension of the conventional ray casting technique.For each viewing direction a(moderate) pre-processing step is performed:the ray traverses the entire volume data (no early ray termination).Its intensity and opacity contributions are divided into several segments which are then sorted and stored by depth.At each sampling position along a segment,accumulated trans-parency and color are stored at a moderate memory overhead.For visualizing real-time volumeclipping,only relevant segment contributions (maximum two) at the location of the clipping plane are considered,thus reducing the calculation to meet real-time requirements.Compared with theprevious work that involves time-consuming re-clipping,re-traversing and re-shading,the proposed method achieves quality identical to ray casting at real-time speed.The performance is indepen-dent of the volume resolution and/or the number of clipping planes along a given viewing direction.Therefore it is suitable for real-time “internal volume inspections“,involving one or several cutting planes,typically applied e.g.,in medical visualization and material testing applications.     

N-烷基-β-氨基丙酸钠的合成与性能

N -烷基 - β -氨基丙酸钠是一类重要的两性表面活性剂 ,除具有一般表面活性剂的性能外 ,还具有低刺激性、抗菌杀菌性等特殊性能。本文以脂肪伯胺为原料 ,经二步反应制得含有单羧酸钠及双羧酸钠的N -烷基 - β -氨基丙酸钠产品。测定了其表面化学性能及应用性能。结果表明该品种是一类性能优良、用途较广的两性表面活性剂。     

Controllable highly regular triangulation

This paper presents a novel algorithm for generating a highly regular triangle mesh under various user requirements. Three scalar fields are first computed on the input mesh. Then, the intersections of their isocontours with one another are used to construct the highly regular mesh result. The proposed algorithm uses the N-symmetry direction field to guide the edge orientation. Size control is achieved by using a density function on the surface. All user requirements are incorporated into an energy optimiza...     

A super-resolution method with EWA

This paper introduces a practical algorithm for super-resolution,the process of reconstructing a high-resolution image from low-resolution input ones.The emphasis of the work is to super-resolve frames from real-world image/video sequences which may contain significant object occlusion or scene changes.As the quality of super-resolved images highly relies on the correctness of image alignment between consecutive frames,the robust optical flow method is used to accurately estimate motion between the image pair.An efficient and reliable scheme is devised to detect and discard incorrect matchings which may degrade the output quality.The usage of elliptical weighted average (EWA) filter is also introduced to model the point spread function (PSF) of acquisition system in order to improve accuracy of the model.A number of complex video sequences are tested to demonstrate the applicability and reliability of the proposed algorithm.     

Behavior of external welded flange-bolted web joints of steel structure exposed to fire

In order to investigate the behavior of external welded flange-bolted web joints of steel structure exposed to fire,a series of experiments were carried out.Influence of fire model and load ratio on the behavior of the joints,failure characteristics and fracture modes of the joints exposed to fire were studied.The experimental results indicated that the fire model has a great influence on the temperature rising as well as temperature distribution of the joints exposed to fire.A slower temperature rising fire will lead to slower temperature rising and more uniform temperature distribution of joint.Decrease of the load ratio will improve the fire-resistant capability of the joint.Furthermore,a highly detailed three-dimensional(3-D) finite element model(FEM) was set up with ANSYS software to predict the behavior of the external welded flange-bolted web joints exposed to fire.Comparisons between the predicted results and the experimental results indicated that FEM has an acceptable degree of accuracy to predict the behavior of this type of joints exposed to fire.