Electrochemical behaviour of 1024 mild steel in slightly alkaline bicarbonate solutions

The electrochemical behaviour of 1024 mild steel electrodes is investigated in the presence of 0.05–0.5 M sodium bicarbonate in aqueous solution at pH 8.9 and 25°C. Voltammograms are obtained with a rotating gold ring-mild steel electrode and the effect of the NaHCO3 concentration, the potential limits and the rotation speed of the disc electrode is considered. The voltammograms display an oxidation peak current at low potentials, a passivity region and a transpassive region at high potentials for the potential sweep in the anodic direction. The oxidation current in the passivity region is practically independent of the applied potential and the NaHCO3 concentration. The rate-determining step of the oxidation reaction in both the oxidation peak current region and the transpassive region is determined.     

DEVELOPMENT TOOL FOR COMPUTER VISION SYSTEMS AT PIXEL LEVEL

This paper describes a tool to aid the development of computer vision applications for pixel-level diagnosis. A conceptual framework for constructing pixel processors is described. The proposed tool is based on two domains: one deals with numerical images, named features, and the other deals with symbolic images, named classes. A reduced set of image and operator types is defined. Based on it, an object-oriented language is described. The main objects define features and classes and their associated operators, namely procedures, classifiers, and rules. All system control is goal oriented and is designed to provide symbolic images as results when a request is received from a higher level of the image understanding system. Some knowledge engineering concepts, such as certainty control and instances, are also included.     

块效应图像质量模糊评估标准

研究和讨论了图像质量评估方法,提出一种基于模糊推理的块效应评估标准。假设图像由平滑区域、边缘区域以及纹理区域等组成,而且不同的区域应采用不同的方法进行质量评估。在此基础上,给出了三个分别适用于不同区域的图像质量评估因子,并提出了一个灵活的模糊图像质量评估方法。此方法把块效应和图像本身具有的边缘分开,防止了边缘会被误认为是块效应。仿真结果表明,提出的标准对于不同的图像具有鲁棒性,有一般图像质量评价标准的性能。     

一种改进的TCP拥塞控制算法

TCP Reno拥塞控制机制是目前互联网中采用的主流拥塞控制算法.根据TCP Reno实现拥塞避免与拥塞控制的AIMD算法中加性因子与减性因子过于武断,对可用带宽的探测缺乏细分,造成信道利用率未达合理水平等缺陷,为此,提出一种根据拥塞窗口的增长情况进行更为平滑的信道容量探测算法,采用基于对数的增长算法和下降算法,通过N...     

基于Lotus Notes的分布式信息商函系统的设计与实现

设计并实现了一种基于Ｌｏｔｕｓ Ｎｏｔｅｓ的分布式信息邮政商业信函系统,并研究了系统实现过程中的两个关键技术。     

Fact-oriented modelling for data analysis

Abstract. Although entity-relationship modelling is the most popular means of specifying the conceptual schema for the data perspective of an information system, an alternative design approach known as fact-oriented modelling appears to offer advantages. This paper provides an overview of fact-oriented modelling, including some recent revisions and an evaluation of how the method has coped with large-scale practical applications. One distinguishing feature of the approach is its emphasis on natural verbalization of information examples in terms of elementary facts. This notion of elementarity is clarified to cater for a problematic case involving compositely identified object types. Finally, the algorithm for mapping a conceptual to a relational schema is revised to cater for lazy object types.     

Transformation calibration of a camera mounted on a robot

The paper describes the accurate calibration of the camera transformation for a vision system consisting of a camera mounted on a robot. The calibration includes an analysis of the linearity of the camera. A knowledge of the camera transformation allows the three-dimensional position of the object points to be determined using triangulation.     

Essential functional role of the polysaccharide intercellular adhesin of Staphylococcus epidermidis in hemagglutination

Hemagglutination of erythrocytes is a common property of Staphylococcus epidermidis strains, which is related to adherence and biofilm formation and may be essential for the pathogenesis of biomaterial-associated infections caused by S. epidermidis. In three independent biofilm-producing, hemagglutination-positive S. epidermidis isolates, interruption of the icaADBC operon essential for polysaccharide intercellular adhesin (PIA) synthesis by Tn917 insertions led to a hemagglutination-negative phenotype. An immunoglobulin G fraction of antiserum to PIA greatly reduced hemagglutination. Purified PIA led to a 64-fold decrease of hemagglutination titers of these strains; however, it did not mediate hemagglutination by itself. These observations define PIA as the hemagglutinin of S. epidermidis or at least as its major functional component.     

Human brain metabolic response to caffeine and the effects of tolerance

OBJECTIVE: Since there is limited information concerning caffeine's metabolic effects on the human brain, the authors applied a rapid proton echo-planar spectroscopic imaging technique to dynamically measure regional brain metabolic responses to caffeine ingestion. They specifically measured changes in brain lactate due to the combined effects of caffeine's stimulation of glycolysis and reduction of cerebral blood flow. METHOD: Nine heavy caffeine users and nine caffeine-intolerant individuals, who had previously discontinued or substantially curtailed use of caffeinated products because of associated anxiety and discomforting physiological arousal, were studied at baseline and then during 1 hour following ingestion of caffeine citrate (10 mg/kg). To assess state-trait contributions and the effects of caffeine tolerance, five of the caffeine users were restudied after a 1- to 2-month caffeine holiday. RESULTS: The caffeine-intolerant individuals, but not the regular caffeine users, experienced substantial psychological and physiological distress in response to caffeine ingestion. Significant increases in global and regionally specific brain lactate were observed only among the caffeine-intolerant subjects. Reexposure of the regular caffeine users to caffeine after a caffeine holiday resulted in little or no adverse clinical reaction but significant rises in brain lactate which were of a magnitude similar to that observed for the caffeine-intolerant group. CONCLUSIONS: These results provide direct evidence for the loss of caffeine tolerance in the human brain subsequent to caffeine discontinuation and suggest mechanisms for the phenomenon of caffeine intolerance other than its metabolic effects on elevating brain lactate.