FTIR Measurement of Cellulose Microfibril Angle in Historic Scots Pine Wood and Its Use to Detect Fungal Decay

Microfibril angle (MFA) – the orientation of cellulose fibres in the S2 layer of the secondary cell wall – is a key determinant of the stiffness and strength of timber. The microfibril angle depends on the way in which the timber was grown and its position within the tree. Microfibril angle can be measured by X-ray diffraction and other methods, but the methods in current use are slow or require advanced instrumentation. The aim of this study was to explore the use of polarised Fourier transform infrared (FTIR) microscopy as a relatively fast and inexpensive method for measuring MFA in historic Scots pine (Pinus sylvestris L.). The FTIR measurements were calibrated against X-ray measurements of MFA in modern Scots pine. We observed a wide range in MFA values and a radial pattern of MFA similar to modern Scots pine in undecayed Scots pine heartwood from sixteenth and seventeenth century beams in Scottish secular buildings. The density of the heartwood was also similar to modern plantation-grown Scots pine despite the much slower growth rate recorded in the ring widths of the historic timber. The sapwood, which had been attacked by both insect pests and fungi, showed an erratic reduction in density and a large increase in MFA compared to the modern material. The increased sapwood MFA was attributed to selective destruction of the S2 layer of the wood cell walls by fungal decay. Using MFA measurements in conjunction with density offers the possibility to estimate the mechanical properties of sound historic pine timber, to detect fungal decay more sensitively than by density alone, and to distinguish between pest and fungal attack in a way that relates directly to the remaining mechanical performance of the timber.     

手机广告——移动中的互动交流

本文以手机广告作为研究对象,通过对手机传播特点的对比分析和对当今应用比较广泛的几种手机广告模式的探讨,总结出手机在广告传播中具有的“移动中的互动交流“的传播特点,进一步分析了目前最符合手机传播特点的广告类型即无线网络广告和无线位置定位广告,并运用哈贝马斯的行为交往理论,揭示了移动中的互动手机广告的深层含义.     

3G时代以智能手机为载体的移动图书馆服务

文章介绍了图书馆基于无线网络提供移动服务的发展情况、3G技术的特点以及读者通过无线网络访问图书馆资源的现状,探讨了以3G智能手机为载体的移动服务架构和服务方式,并对未来的无线技术对图书馆的影响进行了展望。     

移动阅读国内外研究综述

从移动阅读发展趋势、影响移动阅读绩效的指标、移动阅读相关研究方法三个方面对国内外移动阅读的研究情况进行综述,梳理出影响移动阅读绩效的指标体系、应用实验方法和调查方法在相关研究中的应用情况。研究发现,实验方法在我国台湾地区和国外移动阅读研究中应用相对成熟,调查方法在国内大陆地区相关研究中应用较多。最后对国内外移动阅读研究进行简要评析。     

Future Economic Realities for Libraries: A Lesson in Current Events

This article focuses on three current events for learning about what is possible in library policy. The first is the run up in the price of fuel and food (“Too Expensive to Ignore”), the second is the cheapening of some kinds of communication (“Too Cheap to Matter”) and the hugely successful Obama for President Campaign that used the Internet to develop a new way of successful mass fund raising, voter activation and building grass roots support. The author explores the implications of these changes to interpret ALA's late October 2008 request for $100 million in federal funding as the antithesis of successful constituency development for public libraries.     

Managing the Use of Cellular Phones in a Small College Learning Resource Centre

Summary

Seventy-five per cent of young people in Britain own a cell phone. In a survey of sixth form college (small college) Learning Resource Centres (LRCs), cell phone usage occurred regularly and was occasionally a serious problem. LRC Managers need to decide whether to ban cell phone usage or not. Disruptive behaviour in libraries is defined as any behaviour that disturbs other users. Using this criterion, cell phone use should be banned in the LRC. Policies on cell phone use need to be clearly displayed and enforced tactfully and consistently. College management support will increase the effectiveness of any ban.     

Text Messaging in an Academic Library: Integrating SMS into Digital Reference

ABSTRACT

In spring 2005, Sims Memorial Library at Southeastern Louisiana University initiated “Text A Librarian,” a service that enables Southeastern students, faculty, and staff to use the text message feature of their cell phones to send questions to and receive answers from the library. Librarians at Sims use a dedicated text messaging telephone number and “e-mail/SMS” conversion software, provided by Altarama Systems and Services, to send and receive text messages.     

燃料电池产业发展现状分析研究

随着能源危机的愈发严峻以及环境问题的日益严重,高效率,低污染的能源利用方式越来越受到 人们的高度重视。燃料电池是一种高效、洁净的发电装置,它将外界输入的燃料的化学能转化成电能并持续向外供电。这种发电技术不仅缓和了使用化石能源引起的污染排放问题,还提高用电的灵活性和可靠性。在详细阐述燃料电池的分类、国内外技术的发展现状以及当前的发展技术热点后,对燃料电池产业的发展进行全面的现状分析研究。     

一种基于聚类算法的主旨句提取方法

自动文本摘要中一个关键的步骤是确定文章的主旨并将反映文章主旨的句子提取出来.在讨论分析k-means, k-medoids等聚类算法的基础上,根据对文本摘要的实际要求以及文档自身的特点,提出一种基于聚类算法的主旨句提取方法.实验结果表明,在提高聚类准确性的基础上,新方法较其他聚类算法能够更加有效地避免遗漏主题的问题,能较全方位地反映全文的主旨,提取出的摘要既覆盖全面又突出重点.     

一种基于知识元变异的ESI研究前沿知识演进分析方法

[目的/意义]作为一类面向学科领域科技情报需求、针对全文本关键语义计量分析、旨在实现情报自动化到知识自动化实践应用的探索研究,本文基于语义标注和机器学习等技术,在前期研究从知识元共现视角探测研究前沿演进机理基础上,进一步提出一种基于知识元变异的研究前沿知识演进分析方法。[方法/过程]利用Word2vec词嵌入模型将知识元表示为词向量,通过计算知识元向量的欧几里得距离,利用K-means聚类方法识别具有相似语义语用关联的知识元簇集,计算历时簇集内各知识元TF-IDF值,对变异后知识元重要程度的突发变化结果进行定量测度,进而挖掘ESI研究前沿演进中的知识元变异特征和规律。[结果/结论]通过探测结果的对比检验发现,基于知识元变异的科学计量方法,不仅是对前期研究方法的补充和拓展,使得针对研究前沿内部知识运动规律的挖掘更加具体详实,更是在时间序列范畴内,能够尽早、及时探测研究前沿未来发展动向和关键情报信号的有力证据。