含Cl^-溶液中SO4^2-对316不锈钢临界点蚀温度的影响

采用外加恒电位下腐蚀电流-温度扫描方法研究了在0．5％Cl^-溶液中，SO4^2-浓度对316不锈钢点腐蚀行为的影响．结果表明，随着SO4^2-浓度的增加，钝化电流增加，开路电位降低．当SO4^2-浓度低于0．42％时，316不锈钢的临界点蚀温度比不存在SO4^2-时的临界点蚀温度低；当SO4^2-浓度大于0．42％时，临界点蚀温度比不存在SO4^2-时的临界点蚀温度高．从离子竞争吸附的角度进行分析，对SO4^2-加速与抑制点蚀两种作用规律的形成原因进行了解释．     

Fuzzy adaptive networks in machining process modeling: surface roughness prediction for turning operations

Due to the complexity of the machine tool structure and the cutting process, the dynamics of machining processes are still not completely understood. This is especially true due to the demand of high-speed machining to increase productivity. In order to model and control these complex processes, new approaches, which can represent complex phenomenon combined with learning ability, are needed. The combined neural–fuzzy approach appears to be ideally suited for this purpose. In this paper, the recently developed fuzzy adaptive network (FAN) is used to model surface roughness in turning operations. The FAN network has both the learning ability of neural network and linguistic representation of complex, not well-understood, vague phenomenon. Furthermore, it can continuously improve the initially obtained rough model based on the daily operating data. To illustrate this approach, a model representing the influences of machining parameters on surface roughness is established and then the model is verified by the use of the results of pilot experiments. Finally, a comparison with the results based on statistical regression is provided.     

Recover Fault Services via Complex Service-to-Node Mappings in Wireless Sensor Networks

With the motivation of seamlessly extending wireless sensor networks to the external environment, service-oriented architecture comes up as a promising solution. However, as sensor nodes are failure prone, this consequently renders the whole wireless sensor network to seriously faulty. When a particular node is faulty, the service on it should be migrated into those substitute sensor nodes that are in a normal status. Currently, two kinds of approaches exist to identify the substitute sensor nodes: the most common approach is to prepare redundancy nodes, though the involved tasks such as maintaining redundancy nodes, i.e., relocating the new node, lead to an extra burden on the wireless sensor networks. More recently, other approaches without using redundancy nodes are emerging, and they merely select the substitute nodes in a sensor node’s perspective i.e., migrating the service of faulty node to it’s nearest sensor node, though usually neglecting the requirements of the application level. Even a few work consider the need of the application level, they perform at packets granularity and don’t fit well at service granularity. In this paper, we aim to remove these limitations in the wireless sensor network with the service-oriented architecture. Instead of deploying redundancy nodes, the proposed mechanism replaces the faulty sensor node with consideration of the similarity on the application level, as well as on the sensor level. On the application level, we apply the Bloom Filter for its high efficiency and low space costs. While on the sensor level, we design an objective solution via the coefficient of a variation as an evaluation for choosing the substitute on the sensor level.     

Extension of the gap statistics index to fuzzy clustering

The well-known gap statistic index proposed by Tibshirani et al. has successfully applied in many clustering evaluations. However, the gap statistic index cannot evaluate the clustering partitions from any fuzzy clustering algorithm. This is because fuzzy clustering cannot provide the within-cluster similarity measure that is used in the gas statistic index. Thus, the applicable range of the gap statistic index is very limited. In this paper, we present a new method that extends the gap statistic index to fuzzy clustering by using fuzzy membership notations. Our proposed method can extend the applicability of the gap statistic index, and outperform other existing fuzzy indices in several aspects. Experiments on eight sets of synthetic and real datasets are used to verify the applicability and efficiency of the proposed method.     

高压切割喷嘴冲击磨损的数值分析

以复用矿井含煤颗粒的水对高压切割喷嘴的磨损物理问题为研究对象,采用计算流体力学理论进行数值计算,分析讨论了质量浓度为10、15、20、25、30、40 mg/L条件下速度、剪应力、磨损的分布以及变化关系。计算、分析结果表明:磨损主要发生在出口部位和锥体的后半部份,入口部份和锥体前半部份磨损较小;入口部位、锥体部位磨损量、剪应力随质量浓度增加变化较小;出口部位磨损量在质量浓度为10～20 mg/L减小较快,超过20 mg/L后变化不大;出口部位流体速度、磨损量、剪应力与质量浓度间存在对应关系。煤粒入口速度与混合物速度相同、锥体部位煤粒流体速度低于锥体部位混合物速度(平均值)约79.4%;煤粒出口部位速度随质量浓度的增大而呈现先增加后减小的趋势,速度最大值发生在浓度20 mg/L。     

椭圆管外流动熵产及放热系数的数值分析

以椭圆管加热水流动为研究对象,对椭圆管加热水流动系统进行了二维数值模拟。通过联立求解流体力学基本方程和熵产方程,获得了熵产、放热系数与雷诺数和纵、横向间距的变化关系。数值分析结果表明:熵产主要发生在管壁表面附近,而在系统内部区域熵产较小,可以忽略;熵产随雷诺数的增大而增大,随纵、横向间距增加而减小,熵产与雷诺数、纵、横向间距存在对应关系,纵、横向间距宜在1.75～2.0间;在相同的雷诺数值时,熵产、放热系数沿流动方向呈现单调减小的趋势;不同的雷诺数值,熵产、放热系数不同,单调减小的趋势相同。放热系数随Re的增大而增大,且与雷诺数存在对应关系。纵向总放热系数随纵、横向间距增大而减小,且存在对应关系。     

浅谈我国网络数据库的发展及对策

从网络数据库的概念、特点、发展趋势等方面论述了我国网络数据库的发展情况,针对我国网络数据库存在的问题提出了发展我国网络数据库的对策.     

一种完整的汉字识别系统设计

数字图像处理是计算机视觉技术的在交通管理领域的一个重要课题.它是指将图像信号转换成数字信号并利用计算机对其进行处理的过程.字符及汉字识别技术的成功运用,节省了大量的人力,而不影响正常的车辆行驶,并且可以快速的记录车辆的违章情况,它是交通管理自动化中的一项有效手段.本文将介绍一种完整的汉字识别系统设计,实现对36号宋体汉字的辨识.     

开卷机钢卷直径计算优化算法在带钢纵剪生产线中的应用

在带钢纵剪生产线的电气控制系统中,开卷机的钢卷卷径（以下简称卷径）是一个重要的检测参数,其检测和计算的准确性对系统的控制精度影响很大。本文介绍了一种适用于纵剪生产线开卷卷径的测量与计算方法,并且简要说明了如何通过西门子S7-400PLC来实现。经过实际的生产运行证明,该方法可以提高开卷机的实际卷径精度,增强测控系统的稳定性和可靠性。     

光学透射头盔显示器标定综述

光学透射头盔显示器(OSTHMD)标定是增强现实技术研究中一个具有挑战性的关键技术问题.文中详细阐述了OSTHMD的标定技术,包括标定要求、标定计算模型、标定方法、标定评估、发展趋势和应用前景等,重点介绍了比较实用的基于单点主动对准法和基于图像的标定方法.