Word中随意添加会话气泡

编写文档时常常需要针对图片做些注释,比如加上会话气泡等。可使用Photoshop等图像处理软件非常烦琐,不过好在Word2007可以轻松实现添加此类标注的功能。下面就来看看操作过程。     

不一样的Vista气泡屏保

Vista华丽的操作界面一直为广大用户所喜爱,比如其自带的气泡屏保就非常漂亮,当屏保打开后,一个一个彩色的气泡就会从屏幕下方缓缓升起。不过Vista气泡屏保只有一种样式,若想跟别人不同就得上网下载第三方的气泡屏保。其实,我们只要给它动个小手术,就可以轻松拥有不一样的气泡屏保。     

基于CLSVOF方法的三维单个上升气泡运动的数值模拟

运用CLSVOF方法数值模拟了三维单气泡在液体中的上升和变形过程,分别考察了液体的表面张力和浮力对上升气泡变形的影响。计算结果表明:CLSVOF方法能比较精确地跟踪三维单气泡在液体中的上升过程;在相同密度比和粘度比情况下,随着液体表面张力的减小和液体浮力的增大,气泡底部形成的射流使得气泡下缘凹陷变得明显,变形幅度加大,射流穿透气泡的时间提前。     

基于谷点边界扫描及区域合并的浮选气泡提取

针对浮选气泡图像分割难的问题,基于多尺度分析、谷点边界扫描及区域合并的思想提出了一种新的气泡图像分割算法.该算法是建立在多尺度分析和谷点边界跟踪的基础之上的,包括图像预处理,有选择的图像缩小,谷点边界扫描,端点检测及联结,区域合并,缩小图象的分割结果映射到原始图像等步骤,算法可以一次性检测出所有谷点,而不用作图像阈值处理,就可以直接得到谷点边界的二值图像.与基于相似性/Canny边界扫描的算法及分水岭等算法做了对比实验,实验结果表明:1)新算法能够较好地克服气泡破裂及其它噪声的影响,减少过分割现象,具有更好的分割精度;2)其运行速度提高了50～100倍,满足实际应用领域的系统实时性要求.     

射流曝气微细气泡的PIV测量

射流曝气产生的微细气泡是影响氧传质效率的关键。在射流曝气传质学原理的基础上,通过搭建PIV实验台对设计加工的射流曝气器产生的微细气泡直径等参量进行测量。结果表明,其产生的微细气泡粒径小、分布均匀,气泡上浮平均速度小,横向平均速度大、有漩涡。这些特点均有助延长气泡滞留时间或加强扰动,提高氧传质的效果。     

矩形通道内气泡脱离点数值模拟和实验研究

关于过冷流动沸腾气泡脱离点(或称充分发展沸腾起始点,FDB)的研究大多局限在实验研究,缺少预测气泡脱离点的数值模拟模型和方法.建立了数值模拟过冷流动沸腾气泡脱离点的数学模型,利用Fluent实现了对气泡脱离点的数值模拟,并且对矩形通道内的气泡脱离点进行了实验研究.为了验证数值模拟结果的准确性,分别对比了圆管、矩形通道内数值模拟结果和经典模型计算结果,并将双面加热矩形通道内数值模拟结果与实验结果进行对比.分析表明:根据本文模型,可以实现对过冷流动沸腾气泡脱离点位置的数值模拟,而且具有较高的准确度.源于圆管实验的Saha-Zuber模型和Bowring模型适用于双面加热矩形通道.     

直接接触换热器中分散相单个气泡的传热机理研究

基于能量微分方程和质量守恒定律,通过对分散相单个气泡在连续相溶液中的直接接触换热理论分析,建立了分散相单个两相气泡在液体连续相中直接接触换热的传热和气泡生长数理模型.得出了单个气泡在其表面上的平均瞬时换热系数和换热的努谢尔特准则数计算公式,并推导出气泡生长速率的计算关联式.此外,对气泡生长速率的主要影响因素进行分析得出:气泡的生长速率是随速度U和温差ΔT的增加而增大,且增加的速率在前期较快,随后逐渐减慢;气泡的生长速率是随初始半径的增加,先增大后减小的.     

超低碳钢夹杂物控制技术探讨

本文综述了超低碳钢的夹杂物起源,并以日本等先进钢厂的实践经验为基础,对Al2O3夹杂物的产生的工艺过程、影响因素重点进行了讨论,包括渣钢间二次氧化行为、RH处理中夹杂物行为、夹杂物的上浮行为以及铸坯的皮下气泡等.钢包渣改质是控制二次氧化的重要手段,RH加铝前自由氧含量尽可能降低,将浇铸时的氩气量降低均为控制超低碳钢的Al2O3类夹杂物的有效措施.     

Dispersive bubble wall——a new method of flow control in tundish

Tundish is the last refractory vessel in the steelmaking process. The fluid flow phenomena in tundish have a strong influence on the separation of non-metallic inclusions. The dispersive bubble wall （DBW） is a new method in tundish metallurgy. A water model of a multi-strand tundish has been set up based on the Froude number and Reynold number similarity criteria. The effect of DBW＋weir on the flow pattern has been studied. The results show that this new structure of DBW＋weir is beneficial not only to uniform the temperature among different submerge entry nozzles but also to separate non-metallic inclusions from liquid steel. The DBW can capture the particles of non-metallic inclusions and make them float up to the surface.     

Parameters Relevant to Bubble Detachment when Gas-injecting into Polymer Melt Flow Field

The bubble deformation processes were reported when gas was injected into polymer melt flow field in another paper, the experiments showed that the deformation was severely affected by the volume of the bubble, and in turn, for the different bubbles, several different deformation processes were presented during their movement along the flow channel. In addition, we could find that the magnitude of the bubble volume was dependent upon the pressure difference of the gas injection pressure and the melt pressure, In this paper, more experimental conditions were changed to investigate the parameters relevant to the detachment of bubbles from the injection nozzle. The experimental results show that the pressure difference, the melt flow velocity as well as the melt pressure were all critical for the purameters, such as the bubble detachment time, the maximum bubble diometers and the magnitude of the bubble volume. The morphology changes of bubble were very large when the flow field was abruptly changed, and the situations were more complicated.