Epon系统ONU自动发现与注册技术的研究

注册是指新连接的或掉电的ONU加入到EPON系统的过程,ONU的自动发现和注册是EPON系统中ONU和OLT之间能够正常通信的前提保证,是EPON系统可扩展性好、操作维护方便的重要体现.该文分析了对ONU自动加入的基本需求,详细描述了ONU自动加入过程,对两种冲突处理方法进行了分析比较,探讨了注册周期的选取技术,并提出了一种基于注册开窗周期的冲突避让机制.     

27SiMn钢窄间隙GMAW环焊缝开裂原因分析

目的 以发生开裂的27SiMn钢窄间隙GMAW环焊缝为研究对象,研究其裂纹形成原因及扩展过程。方法 对裂纹附近的母材及焊缝进行化学成分分析、裂纹宏观形貌分析、金相组织分析、扫描电镜分析、结构受力分析等,探明裂纹的形貌特征、形成原因及扩展路径。结果 试样化学成分和金相组织无明显异常,满足使用要求。裂纹属于明显的张开型（Ⅰ型）裂纹,从焊缝根部向缸体表面呈碗状扩展,形成缸体内部与外部的连接通道,导致液压油渗漏。裂纹起源于焊缝根部的热影响区,焊缝根部熔深不稳定,部分拼接处存在未熔透缺陷,未熔透处存在的氧化铝、碳酸钙等夹杂物是形成裂纹的主要诱因。在焊接残余应力的作用下,沿焊缝根部的夹杂物形成轴向裂纹和周向裂纹;在工作载荷的作用下,焊缝根部周向拉应力和轴向拉应力达到最大值,其中周向拉应力约为工作载荷的5.5倍,在周向拉应力的作用下,裂纹沿径向和轴向发生扩展,最后形成碗状的裂纹扩展面。结论 焊缝根部的未熔透缺陷和非金属夹杂物是产生裂纹的主要原因,在工作载荷的作用下,裂纹沿轴向和径向发生扩展,最后扩展至缸体表面呈碗状。     

单色光释光仪的研制

介绍了一种自行设计,开发的单色光释光仪,编写了一套专用的软件,包括仪器控制和管理程序,数据采集与分析程序,该仪器由计算机控制,简单实用,操作方便。     

一种改进的OL归结——SOL归结

1973年,Chang和Lee将线性归结与有序归结相结合,提出了有序线性归结,即OL归结,极大地提高了线性归结的效率和机械性。然而,OL归结并不是一种完备的归结方法。在OL归结的约化条件的基础上提出了强约化的概念。强约化条件对中心有信息有序子句的约化做了进一步的限制,且该强约化条件是约化条件的一种特例。在强约化条件的基础上,还提出了一种改进的OL归结——SOL归结,并证明了其完备性。     

自动送样激光释光仪

介绍了一种自行设计的可连续测试20个样品的释光仪器,该仪器用半导体激光器作为激发光源,半导体激光器采用光纤输出,光斑大小和光功率可调;同时对仪器的功能结构作了简单的介绍。     

光释光仪器的激发光源

光释光应用与研究发展二十多年来,在矿物研究、地质样品年龄测定以及考古等领域,光释光仪器有着举足轻重的地位,而光释光仪器激发光源的优劣决定着仪器测量的准确性,本文在分析各种激发光源的基础上,提出了用半导体激光器作为激发光源的新方案,列出了红外和蓝光输出半导体激光器的输出参数测试结果,说明了使用方法,并分析了半导体激光器的优点.     

Anaerobic digestion of maize and cellulose under thermophilic and mesophilic conditions – A comparative study

The aim of this study was to advance in understanding of digestion process of energy crops. Cellulose and maize silage were fermented in batch mode at mesophilic (38 °C) and thermophilic (55 °C) conditions and corresponding organic loads of 5.5 ± 0.2 kgVS/m³, 11.2 ± 0.3 kgVS/m³ and 16.7 ± 0.4 kgVS/m³.For both substrates more stable and faster digestion took place at 38 °C. Due to complex structure maize degradation was characterized by varying digestion rate and longer total digestion time resulting form breakdown of hard-degradable fractions. The digestion retard at increased OLRs of cellulose and lower degradation level obtained for all cellulose series confirm a higher overloading potential for systems dealing with single-component-substrates but also the enhanced sensitivity of such systems to any inconvenient digestion conditions.Based on observed patterns of volatile fatty acids and oxidation-reduction potential, different fermentation mechanisms can be concluded for cellulose and maize, but also for different temperature modes. Conversion of maize at highly reductive conditions with increased concentrations of butyric acid was accompanied by much higher activity of hydrogenotrophic methanogens than for cellulose digestion.Two factors showed a strong potential to influence test results: an insufficient VS content of inoculum, which caused reduced biogas yields, and a high natural biodiversity of maize silage, resulting in higher biogas yields than calculated based on the maize composition.     

Doubly deterministic tabled OL systems

A tabled OL system is doubly deterministic if its tables (developmental programs) are deterministic and its choice of table is also deterministic. Numerous results on DDTOL systems are presented, mainly decidability results. The putative biological importance of the model is also discussed and its choice motivated.Work carried out partially under the auspices of the Universities of Antwerpen, Karlsruhe, and Utrecht and partially under Natural Sciences and Engineering Research Council of Canada Grants Nos. A-7403 and A-7700.     

ICT-supported knowledge representation for development of routines in industry

Organizational Learning (OL) is important for a firm’s productivity growth. According to some literatures, information and communication technology do not support organizational learning and therefore not enhanced productivity. This research however has demonstrated that in the case of manufacturing companies some computer-based systems representing organizational knowledge—knowledge management systems (KMS) do support organizational learning. For OL to take place through KMS, our findings suggest that a deliberate organizational learning structure must be in place within the organization. This article demonstrates how knowledge management systems deliberately developed and implemented by management, can support the development of operating routines for manufacturing industries. KMS, if deliberately implemented for the purpose of empowering employee participation, may be a supporting mechanism for process and product improvement and innovation in manufacturing organizations. Such a structure may results, as our case demonstrates, in a dynamic and iterative employee—management knowledge development process resulting in productivity enhancement.