弧齿锥齿轮数控加工和齿面接触点求解算法研究

在保证弧齿锥齿轮加工过程中刀盘相对于工件的运动关系不变的基础上,通过矩阵变换实现铣齿加工的数控展成.由于在数控加工每个插补周期中难以实现这种涉及大量运算的运动转换,因此将数控坐标轴的展成运动表示为以工件齿轮转角为参数的五次参数样条函数,保证了插补的实时性和精确性.文中将传统用于确定接触点位置时求解非线性方程组的问题,转化为带有3个设计变量的约束优化问题,简化了法线重合的条件,建立配对齿轮位置矢量相等的目标函数.最后给出实例对算法进行了说明和验证.     

Generating planar spiral by geometry driven subdivision scheme

Spirals are curves with one-signed, monotone increasing or decreasing curvature. They are commonly useful in a variety of applications, either for aesthetic or for engineering requirements. In this paper we propose a new iterative subdivision scheme for generating planar spiral segments from two points and their tangent vectors. The subdivision process consists of two main steps, computing new points and adjusting tangent vectors adaptively for each iteration. We categorize this iterative scheme as geometry...     

艺术设计的裂变与传承

对历史的再思索可以为未来指明方向,艺术设计在裂变与传承的哲学思辨中循着否定之否定的螺旋式规律发展演变。在对高度理性的现代主义风格的反思中,一个新的感性时代正在来临。论文通过对设计发展轨迹的思索,探讨设计发展的内在规律。以此为基础,对当今设计发展趋势和动力进行分析研究。     

Study of tool trajectory in blisk channel ECM with spiral feeding

Electrochemical machining (ECM) plays an important role in blisk manufacturing. There are two steps in blisk ECM: machining of channels and precise shaping of blade profiles. In channel machining, channels are machined in the workpiece with allowance left to the following process. Therefore, the main aim of channel machining with ECM is to improve the allowance distribution. With this aim, a new ECM method for blisk channels, spiral feeding ECM, is developed in which the cathode feeds from blade tip to hub along with rotation motion around its axis. Through this combined motion, twisted channels are produced in the workpiece. The relationship between feed position and rotation angle is presented in the form of a mathematical model. Experiments with a feed rate of 1 mm/min confirm that spiral feeding ECM is feasible and efficient. Compared with radial ECM, the allowance differences in blank back and blank basin decrease by 32.7% and 33.6%, respectively. The surface roughnesses Ra in blank back, blank basin, and hub are 0.358, 0.308, and 0.102 µm, respectively. Thus, the allowance distribution is improved to be more uniform considerably and the surface quality is relatively high.     

Improved statistics of sub-mesoscale eddies in the Baltic Sea retrieved from SAR imagery

In the present article the spatio-temporal distribution of sub-mesoscale eddies seen in Envisat Advanced Synthetic Aperture Radar (ASAR) imagery of the Baltic Sea is discussed. A total of 1250 ASAR images acquired between 2009 and 2011 form the basis of our studies and show imprints of almost 7000 sub-mesoscale eddies. Since the visibility of vortical structures in synthetic aperture radar (SAR) imagery significantly depends on the near-surface wind speed, wind data from a numerical model of the Baltic Sea were additionally used to obtain improved eddy statistics. Seasonally averaged fields of near-surface wind speed, surface currents, sea surface temperature (SST), and SST gradient were also analysed in order to reveal the role of these hydrophysical parameters in the observed spatial and temporal variation of sub-mesoscale eddies.     

图像中对数螺旋线的拟合

针对图像中存在的对数螺旋线形状,提出了一种有效的对数螺旋线拟合方法。首先根据螺旋线的性质将已知图像中螺旋线的中心点约束在一个较小的区域内进行搜索,然后将从图像中获取的直角坐标系下的数据点通过坐标变换转换为能用直线形式表示的数据点,将对对数螺旋线的拟合转换为对直线的拟合。这一方法能快速、准确地拟合出图像中存在的对数螺旋线。     

转炉废水处理与回收利用

采用湿法除尘方法研究转妒除尘，在生产条件下，通过湿法除尘后，废水中绝大多数悬浮颗粒被除去，悬浮物稳定在一定范围，便于循环利用；污泥回收利用。     

螺旋CT的应用及优势

本文介绍了螺旋CT的引进情况，阐述了螺旋CT的原理和在应用中的良好表现，并把螺旋CT与普通CT、多层螺旋CT与单层螺旋CT分别作了比较，优劣非常明显。     

亚洲沙尘影响台湾期间大气悬浮微粒之粒径大小及化学组成变化趋势

旨在针对2002年3￣4月亚洲沙尘影响台湾期间,探讨位于台湾海峡中间澎湖群岛之大气悬浮微粒物化特征变化情形。本研究在澎湖群岛的小门村设置悬浮微粒采样站,借以采集近海面之大气悬浮微粒。由悬浮微粒浓度变化情情得知,2002年3￣4月共有3次亚洲沙尘暴抵达澎湖群岛,其粒径分布很明显地由双峰分布(bi-modaldistribution)转变为以粗微粒(coarseparticle)为主之单峰分布(singlemodaldistribution)。此外,悬浮微粒中水溶性离子成分之粒径分布亦随亚洲沙尘之抵达而呈明显变化,其中Cl-和Na+之变化趋势具有一致性,显示海盐之影响颇为重要;NH4+、Ca2+和SO42-均由细微粒(fineparticle)转变为粗微粒,显示(NH4)2SO4或CaSO4应为亚洲沙尘之特征指纹;NO3-主要来自当地污染(localemission),故其分布并无明显变化;Mg2+虽维持以粗微粒为主之单峰分布,但其浓度却增加约2倍左右。上述研究结果显示,当亚洲沙尘抵达台湾地区,不仅悬浮微粒之粒径大小改变,就连化学组成亦出现明显变化。     

热交换器材料优化研究

对内螺纹铜管尺寸优化、铝箔厚度减薄前后的空调热交换器进行了单体性能实验和整机性能实验对比。实验结果表明优化后的内螺纹铜管、铝箔完全满足使用要求，为节约空调热交换器材料提供了有力的依据。