对我国数字图书馆建设的三点思考

稳步推进数字图书馆工程是多数国家信息基础建设的重要任务,也是我国社会发展的重要战略之一．数字图书馆进入我国十余年,尚处于初级阶段。我国的数字图书建设在规划、定位、服务、资源管理等方面需要深入思考与探索,这是当前的我国数字图书馆建设的重要课题之一。     

基于BP神经网络的模糊PID风量控制

针对煤矿主风机通风系统多变量、非线性、时变滞后性等问题,提出一种基于BP神经网络的模糊PID算法。该算法综合神经网络、模糊控制与PID调节的各自优点,既具有神经网络的自学习和自适应能力,又具有模糊控制的非线性控制作用,同时兼备PID调节的广泛性。仿真结果表明,该算法的响应速度、稳态精度均优于传统的PID调节,取得比较理想的控制效果。     

热喷涂技术及其在铁路行业中的应用

综述了表面工程及热喷涂技术的特点及发展，重点综述了热喷涂技术在工程中，尤其是在铁路行业中的应用。热喷涂技术作为表面工程技术的一个重要分支，在铁路行业中的应用前景极为广阔，进一步推广应用该技术将产生较大的经济和社会效益。     

Investigation on replication of microfluidic channels by hot embossing

In this study, effects of embossing temperature, time, and force on production of a microfluidic device were investigated. Polymethyl methacrylate (PMMA) substrates were hot embossed by using a micromilled aluminum mold. The process parameters were altered to observe the variation of replication rate in width and depth as well as symmetry of the replicated microfluidic channels. Analysis of variance (ANOVA) on the experimental results indicated that embossing temperature was the most important process parameter, whereas embossing time and force have less impact. One distinguishing aspect of this study is that, the channels were observed to be skewed to either side of the channel depending on the location of the protrusions on the mold. The mechanism of the skewness was investigated by finite element analysis and discussed in detail. Results showed that the skewness depends on the flow characteristics of the material and could be reduced by increasing the embossing temperature. The best replication rates were obtained at parameter settings of 115°C, 10?kN, and 8?min for the molds with minimum 56?µm wide features of 120?µm depth. We also showed that the fabricated channels could be successfully sealed by solvent-assisted thermo-compressive bonding at 85°C under 5.5?kN force.     

纳米孔传感技术应用于肿瘤早期诊断的研究进展

近几十年来,尽管研究人员一直在努力开发新的诊断和治疗技术,癌症仍然是世界上发病率和死亡率最高的疾病之一。其中关键点是在肿瘤发生的早期进行诊断。现有的肿瘤早期诊断方法有很多缺点,比如对病患肿瘤组织的侵入。因此,与肿瘤相关的无创诊断的研究已经越来越多并已经取得进展。研究发现,蛋白、DNA或者RNA等生物大分子都有可能成为潜在的肿瘤标志物,已有的检测方法也存在许多缺点。纳米孔因具有独特的物理和电学性质,对生物分子的检测有快速、无需标记和扩增等优点,已被广泛使用和证明。在不远的将来,应用纳米孔对肿瘤标志物进行检测,进行肿瘤诊断并监控治疗过程值得期待。主要介绍了纳米孔传感技术应用于肿瘤早期诊断中肿瘤标志物检测的研究进展。     

On spiking neural P systems and partially blind counter machines

A k-output spiking neural P system (SNP) with output neurons, , generates a tuple of positive integers if, starting from the initial configuration, there is a sequence of steps such that during the computation, each O _i generates exactly two spikes aa (the times the pair aa are generated may be different for different output neurons) and the time interval between the first a and the second a is n _i . After the output neurons generate their pairs of spikes, the system eventually halts. We give characterizations of sets definable by partially blind multicounter machines in terms of k-output SNPs operating in a sequential mode. Slight variations of the models make them universal.     

Tree-systems of morphisms

Starting from the idea of determinism in membrane systems, we introduce a language generating device consisting of morphisms placed in the nodes of a tree. Initial strings are given in the leaves; by iteratively applying the morphisms to them, we produce new strings, which are collected in the root of the tree. Such a device is called a tree-system of morphisms (in short, a T system). We investigate here the power of T systems, both in the extended (a terminal alphabet is considered and only strings over it are accepted) and non-extended case, mainly in comparison with classes of languages in Lindenmayer hierarchy. Received: 8 February 2001 / 18 September 2001     

Impact of computer training courses on reduction of loneliness of older people in Finland and Slovenia

Previous research has shown loneliness as a threat for the quality of life of older people; therefore the goal of the intervention in a quasi-experimental study was to evaluate and discuss the self-reported level of loneliness of older people in Finland and Slovenia before and after a computer intervention. Intervention in a quasi-experimental study was conducted among 58 older participants at the baseline (M = 72.4 years) and 45 older participants at the follow-up research study (M = 72.9 years). Inferential statistics showed a significant difference in the reduction of loneliness between the countries, and a decreased level of loneliness of older people after completing the computer training course. Although older people experience many age-related problems which may reduce their interest in learning information and communication technology (ICT) skills, it is important that they are computer-proficient, because computer engagement can reduce the level of loneliness of older people and in this way has a positive effect on their quality of life.     

江汉油区出砂油井治理技术研究

经过40年的开发,江汉油区地层出砂越来越严重,致使作业维护井次逐年上升,严重影响了油井的正常生产。根据江汉油区出砂储层地质特征和出砂井生产现状,有针对性地开展出砂井井筒清砂和携砂举升采油技术研究或矿场试验,使出砂井治理收到了一定效果,缓解了地层出砂对油井生产的影响,为进一步开展出砂油井治理指明了主攻技术方向。     

基于指数神经元的模型感知器的设计

基于神经元感知器结构并采用最速下降自适应算法，针对电导，温度，湿度，水分，浓度，油粘度等测量问题设计一种基于指数神经元的自适应模型感知器，同时在一定意义上实现了信息融合。分析讨论了学习参数对感知器建模工作性能的影响，给出了电导，温度，水分应用实例的仿真曲线。结果表明，所设计的自适应模型感知器应用于传感器及测量系统的自动建模是有效的。该种建模方法和机制也可作为智能单元（硬件或软件）灵活地应用于实际测量或控制系统，从而取代传统的人工曲线拟和方法。