汽轮发电机组突发性振动故障分析和处理

某厂2号机在启动升速到2900r／nin左右或带负荷运行过程中，汽轮机1号、2号轴承振动经常突然增加到100μm以上，降低润滑油温或提高润滑油压可以消除异常振动，换用新汽轮机转子以后再次出现上述振动现象，试验分析发现主要原因是汽轮机与发电机转子连接后对轮晃度较大及汽轮机转子残余不平衡量偏大。针对上述问题分别进行处理后，消除了汽轮机存在的突发性振动。     

一种快速的浓淡算洁及其实现

高逼真度浓淡效果的生成需要巨大的运算量，这使其很难用于实时计算机成象（ＣＩＧ）系统．本文从几何角度出发，在对整个三角形面元进行角度的增量化线性内插基础上，提出了一种具有高光效果的浓淡图形实时绘制算法，并给出了其硬件实现方法．     

一种改进的Phong浓淡处理技术

本文提出了的改进的Ｐｈｏｎｇ浓淡处理技术，无须对多边形进行任何预处理，通过对漫反射明暗度和表面法矢及Ｈ矢量的双线性插值，保证了显示效果，并将算法效率提高３５～４０％。     

A Study of the flow phenomenon of water in a channel with flat plate obstruction geometry at the entry

The flow ina parallel walled test channel, when obstructed with a geometry at the entrance, can be forward, reverse and stagnant depending on the position of the obstruction. This interesting flow phenomenon has potential benefit in the control of energy and various flows in the process industry. In this experiment, the flat plate obstruction geometry was used as an obstruction at the entry of the test channel. The parameters that influence the flow inside and around the test channel were the gap (g) between the test channel and the obstruction geometry, the length (L) of the test channel and the Reynolds number (Re). The effect of the gap to channel width ratio (g/w) on the magnitude of the velocity ratio (V₁/V₀ : velocity inside/ velocity outside the test channel) was investigated for a range of Reynolds numbers. The maximum reverse flow observed was nearly 20% to 60% of the outside velocity for Reynolds number ranging from 1000 to 9000 at g/w ratio of 1.5. The maximum forward velocity inside the test channel was found 80% of the outside velocity at higher g/w ratio of 8. The effect of the test channel length on the velocity ratio was investigated for different g/w ratios and a fixed Reynolds number of 4000. The influence of the Reynolds number on the velocity ratio is also discussed and presented for different gap to width ratio (g/w). The flow visualisation photo-graphs showing fluid motion inside and around the test channel are also presented and discussed.     

A naphthalene sublimation study on heat/mass transfer for flow over a flat plate

It is important to completely understand heat/mass transfer from a flat plate because it is a basic element of heat/mass transfer. In the present study, local heat/mass transfer coefficient is obtained for two flow conditions to investigate the effect of boundary layer using the naphthalene sublimation technique. Obtained local heat/mass transfer coefficient is converted to dimensionless parameters such as Sherwood number, Stanton number and Colburnj-factor. These also are compared with correlations of laminar and turbulent heat/mass transfer from a flat plate. According to experimental results, local Sherwood number and local Stanton number are in much better agreement with the correlation of turbulent region rather than laminar region, which means analogy between heat/mass transfer and momentum transfer is more suitable for turbulent boundary layer. But average Sherwood number and average Colburnj-factor representing analogy between heat/mass transfer and momentum transfer are consistent with the correlation of laminar boundary layer as well as turbulent boundary layer.     

利用工业厂房内环形接地扁钢作PE干线的验算

通过工程实例验算,讨论了工业厂房内利用接地扁钢作PE干线的合理性和可行性,并对其截面的选择提出建议。     

Mobile Surface Reflectometry

We present two novel mobile reflectometry approaches for acquiring detailed spatially varying isotropic surface reflectance and mesostructure of a planar material sample using commodity mobile devices. The first approach relies on the integrated camera and flash pair present on typical mobile devices to support free‐form handheld acquisition of spatially varying rough specular material samples. The second approach, suited for highly specular samples, uses the LCD panel to illuminate the sample with polarized second‐order gradient illumination. To address the limited overlap of the front facing camera's view and the LCD illumination (and thus limited sample size), we propose a novel appearance transfer method that combines controlled reflectance measurement of a small exemplar section with uncontrolled reflectance measurements of the full sample under natural lighting. Finally, we introduce a novel surface detail enhancement method that adds fine scale surface mesostructure from close‐up observations under uncontrolled natural lighting. We demonstrate the accuracy and versatility of the proposed mobile reflectometry methods on a wide variety of spatially varying materials.     

发带头发模型的快速渲染及发型控制

为了解决虚拟人头发仿真中由于头发数量巨大导致的实时渲染难、发型单一的问题,提出了一种改进的、可实现多种发型的发带头发模型仿真方法。对基于NURBS曲面的头发模型定位控制点时,采用悬梁臂模型表现出头发自然下垂的状态。对传统的Phong光照模型,提出一种快速精确计算反射方向的改进方法,并考虑头发纹理和Phong明暗处理的相互作用。此外,提出一种新颖的发型设计方法,即通过对alpha纹理的控制和对纹理映射施加扰动函数实现不同头发长短和弯曲的造型。实验结果表明,新的方法能快速实现具有高逼真度的虚拟人头发仿真,且支持多种发型。     

基于边界轮廓的区域生长算法在RBC提取中的应用

提出一种基于边界轮廓的区域生长算法提取各个细胞的图像,并运用阴影恢复技术进一步得到每个细胞的三维高度场数据,这些三维数据可用于计算细胞表面曲率。整个提取算法分为三个步骤：轮廓跟踪、区域生长、基于SEM成像条件的三维形状重建。考虑到重叠细胞的统计特征,只需提取处在最上层的细胞。实验结果表明,该方法具有很强的可行性和实用性。     

Towards Perceptual Simplification of Models with Arbitrary Materials

Real‐time rendering of models with high polygon count is still an important issue in interactive computer graphics. A common way to improve rendering performance is to generate different levels of detail of a model. These are mostly computed using polygonal simplification techniques, which aim to reduce the number of polygons without significant loss of visual fidelity. Most existing algorithms use geometric error bounds, which are well‐suited for silhouette preservation. They ignore the fact that a much more aggressive simplification is possible in low‐contrast areas inside the model. The main contribution of this paper is an efficient simplification algorithm based on the human visual system. The key idea is to move the domain of error computation from image‐space to vertex‐space to avoid a costly per‐pixel comparison. This way the error estimation of a simplification operation can be accelerated significantly. To account for the human vision, we introduce a perceptually based metric depending on the contrast and spatial frequency of the model at a single vertex. Finally, we validate our approach with a user study.