印刷胶片的自然老化与人工老化的关系

几种不同型号的印刷胶片以温度50℃、相对湿度80%的条件进行1—4天的人工老化试验,所得的结果与自然保存1至2年的同样胶片性能进行分析比较。自然保存是在有空调和无空调两种环境条件下进行的,前者是温度21℃±3℃,相对湿度50%—65%;后者是当地的自然条件,冬天最低为-8℃,夏天最高达40℃,湿度变化范围更大。本文对此进行详细阐述。     

A Note on EMQ Under Learning and Forgetting

We amplify and extend a paper on the subject by Sule.     

Ageing of dealloyed copper

A finely divided copper rod structure has been prepared by the selective dissolution of aluminium from a Cu-50wt% Al alloy in aqueous NaOH. The aging behaviour of this product has been studied by measurement of the coarsening of the pore and copper rod structure. A decrease in caustic concentration or temperature was found to reduce the rate of coarsening. The leaching reaction was found to play no part in the coarsening process. A dissolutionr-eprecipitation mechanism, where copper dissolves from faults within the structure and reprecipitates on adjacent copper rods was found to account quantitatively for the development of the coarsening process in its early stages. However, this model breaks down after extended times when the rod geometry is destroyed.     

芳纶APMOC的热老化

采用高温干燥箱在100℃、120℃、150℃条件下研究了热老化对阿莫斯(APMOC)结构与性能的影响,并对老化试样进行了单丝拉伸测试及相应的结构分析。实验表明,在实验温度范围内,APMOC不存在明显分子结构的变化;在100℃,120℃处理条件下,由于结晶度的增加,纤维性能有轻微上升,而150℃处理使力学性能下降,且强度变化比模量变化明显;热老化对纤维性能影响的总体趋势是使其脆化,伸长率下降,通过老化前后拉伸断口的扫描电镜(SEM)观察结合纤维自身皮芯结构的特点,解释了老化前后纤维失效形式从原纤劈裂到脆性断裂的微观机理。     

成组生产下的考虑学习和遗忘效应的调度策略

以成组生产的单机系统为对象,提出一种新的考虑学习遗忘效应的成组调度模型,使得建立的调度模型更加符合实际.以总makespan最小为目标,模型中同时考虑了与调度策略有关的设置时间、实际加工时间.基于成组生产的特点,考虑到设备加工相同、相似的零件时的学习效应,转换零件类型造成学习效果衰退的遗忘效应,提出用三个模型来表达成组生产中零件实际加工时间.最后,通过算例分析及结果分析说明了模型的有效性.     

Ageing and piezoresistance of island manganese films

Island manganese (Mn) films of mass thicknesses 2, 4, 6, 8 nm were deposited on Corning 7059 glass substrates at ambient temperature. The deposition took place in vacuum by the thermal evaporation technique. The dependence of the d.c. resistance of the as-deposited Mn films on time (ageing) was studied in air at a room temperature of 20 C over a period of 110 H. It was found that the increase in resistance lasts for relatively short intervals, in comparison with many other island films, before the resistance attains a stable value. The length of the time intervals decreases with increase of film thickness. The response of the stabilized Mn films to longitudinal and transverse induced strains was investigated and the corresponding gauge factors were deduced. The gauge factor increases with decrease of film thickness. The sensitivities of the present films to the two types of strain are comparable. The data of the research are discussed with the view that the quantum mechanical tunnelling model is the mechanism responsible for the electrical conduction in our films.     

Ageing mechanisms and reliability of graphene-based electrodes

The development of flexible transparent electrodes for next generation devices has been appointed as the major topic in carbon electronics research for the next five years. Among all candidate materials tested to date, graphene and graphene based nanocomposites have shown the highest performance. Although some incipient anti-oxidation tests have been reported, in-deep ageing studies to assess the reliability of carbon-based electrodes have never been performed before. In this work, we present a disruptive methodology to assess the ageing mechanisms of graphene electrodes, which is also extensible to other carbon- based and two-dimensional materials. After performing accelerated oxidative tests, we exhaustively analyze the yield of the electrodes combining nanoscale and device level experiments with Weibull probabilistic analyses and tunneling current simulation, based on the Fowler-Nordheim/Direct-Tunneling models. Our experiments and calculations reveal that an ultra-thin oxide layer can be formed on the pristine surface of graphene. We quantitatively analyze the consequences of this layer on the properties of the electrodes, and observed a change in the conduction mode at the interface （from Ohmic to Schottky）, an effect that should be considered in the design of future graphene-based devices. Future mass production of carbon-based devices should include similar reliability studies, and the methodologies presented here （including the accelerated tests, characterization and modeling） may help other scientists to move from lab prototypes towards industrial device production.     

Ageing of fresh and used Ca-Sr-cuprate-based catalysts

An ageing degeneration process was observed in a Ca-Sr-cuprate catalyst, both unused and after use in an NO decomposition reaction. The formation of strongly interacting dipoles (SIDs) by Cu²⁺ and oxygen ions perturbs the layerlike structure, which is typical of Sr₃Cu₅O₈ species and is also characteristic of the present catalyst when it is fresh. This phenomenon was observed with both unused and used aged samples. Furthermore, in the case of the used catalysts, the degeneration process lead to the disappearance of both the layerlike crystal structure and of the SID systems. However, the samples recover their properties when recalcined.     

Ageing of two petroleum waxes

The effect of ageing at different storage conditions on the microstructure and melting properties of two petroleum waxes, petrolatum and microcrystalline wax, were investigated. The two waxes were stored for a maximum of 50 weeks at different temperatures. Samples were analysed before storage and removed from storage and analysed after different storage times. The effect of storage time and temperature was analysed with confocal laser scanning microscopy and modulated differential scanning calorimetry. Some alteration in the microstructure occurred with longer storage time. The amount of fine and irregular structures seen in the initial petrolatum samples decreased with storage time, and some shadowy, grey areas appeared. The microstructure of the microcrystalline wax stored at 23 °C became more diffuse and more, shadowy, grey areas appeared with time compared to samples stored at 50 °C. These showed coarser crystalline structures and fewer shadowy, grey areas. The results of confocal laser scanning microscopy and modulated differential scanning calorimetry analyses indicated that recrystallization occurred in both waxes during storage. The proposed recrystallization processes taking place during storage were most likely the same in all samples, but the recrystallization occurred to a greater extent in the microcrystalline wax samples stored at 50 °C.     

Publications and patents in nanotechnology

Nanotechnology and the sciences that are associated with it have attracted much attention. Experts from various fields believe that nanotechnology will be one of the key technologies affecting almost every aspect of the economy. While there are considerable efforts underway that aim to commercialise nanotechnology - carried by start-up companies as well as large internationally operating firms -, most of the activity seems to focus on research and development activities. There have been a number of technology studies and investment reports that describe the opportunities associated with this emerging area. Over the years there have also been a number of bibliometric and patent studies that examined the field. This paper provides an overview of measuring nanotechnology with commonly used indicators of bibliometric and patent analyses. This revised version was published online in June 2006 with corrections to the Cover Date.     

磁记录带的吸湿及老化

本文是美国国家航空与航天管理局E.F.Cuddihy发表的,有关采用聚氨基甲酸乙酯制成氧化物涂层及背层的宽频仪器用聚酯磁记录带的吸湿及水解老化特性的学术研究报告摘编．     

碳纤维复合材料单向板耐候性及湿热老化性能

通过模拟环境因素对碳纤维增强树脂基复合材料(CFRP)板的耐候性及湿热老化性能进行了检验,研究了CFRP板的抗拉强度、弹性模量及断裂伸长率随严苛环境下的暴露时间的变化规律。研究表明强紫外线、湿冷环境和酸碱侵蚀对CFRP板性能影响较大,90天周期内拉伸强度下降了10%左右,拉伸模量下降15%左右;纯水、盐溶液及加速湿热老化的影响则并不十分显著。扫描电镜观察发现,绝大多数侵蚀性破坏首先发生在树脂层,提高基体树脂的性能将有助于增强CFRP的耐久性。     

老龄化背景下乐龄游戏探析

目的评述乐龄游戏研究进展,分析乐龄游戏发展现状和方法应用,探究乐龄游戏面临的挑战和发展趋势。方法基于文献研究和实地调查,全面分析面向老年人的乐龄游戏特点及游戏种类并总结其优劣势。通过整合游戏技术类别,对移动端类、电子类、交互类、VR类乐龄游戏的硬、软件开发手段进行分析,同时结合人本主义理论、情感化理论、熟悉度理论、包容性设计、心流理论的设计方法及评价指标评定,深入挖掘国内乐龄游戏发展机会及其所面临的困境。结论分析乐龄游戏在人机交互安全性、交互流畅性、硬软件设计的合理性及技术上存在的问题并在市场上、技术上和应用上的发展趋势,以期为乐龄游戏后续研究提供有益借鉴。     

数码照片档案的老化研究

随着社会的进步,形成的数码照片档案日益增多,同时,它发生着变黄、褪色等老化现象也越来越严重,这主要是受周围的保管环境和制成材料的作用导致的。因此,我们必须对它进行数据维护和日常维护,以保证它的耐久性。     

The Effect of Alternate Periods of Learning and Forgetting on Economic Manufacturing Quantity

A method for incorporating the effects of learning and forgetting in the calculation of economic manufacturing quantity is presented. A solution procedure is derived and illustrated by an example.     

Ageing behaviour of commercial aluminium-lithium welds

The post-weld ageing behaviour of two commercial aluminium-lithium alloys, 2090 and 8090, was evaluated. Both a 2319 and 5556 filler material were used for preparing welds in Alloy 2090, while only the 5556 filler material was used with Alloy 8090. Welds with these filler metals were made at two dilution levels, nominally 35% and 65% dilution of the filler material by the base metal. The ageing behaviour of autogenous welds in each alloy was also evaluated. Post-weld heat treatments were performed at 325, 375 and 475°F (163, 190 and 218°C) for times up to 32 h. The ageing response was determined by performing hardness measurements at 4 h intervals. In general, dilution of the base metal by the filler metal reduced the ageing response of the combinations tested with autogenous welds in both 8090 exhibiting the highest peak hardness values. Ageing response curves for six base metal/weld metal/dilution combinations at two autogenous welds at three temperatures are presented.