校园网资源整合与校园云服务模式研究

云计算应用正以势如破竹的态势进入到教育领域,云计算的推广有利于教育资源的共建共享,方便师生快捷地获取所需资源和服务,更高效地开展学习和科研工作.分析了现有网络资源的具体实际情况,利用云计算技术,探究资源整合的有效方式,整合校园网资源,探索适合于教师教学与科研、学生学习与成长,以及学校提升社会服务能力的校园私有云服务模式.     

使用PKCS#11标准实现OpenVPN硬件加密算法

随着企业对使用互联网的安全需求大幅提高,VPN技术成为重要的解决方案。OpenVPN作为Linux下开源VPN的先锋,得到了广泛研究和应用。采用PKCS#11标准将硬件加密设备(KEY,一种智能密码钥匙)接入OpenVPN,使身份验证所需的数字证书能够通过硬件读写、存储,并且使VPN加密算法及加密/解密过程能够通过硬件实现,从而进一步提高OpenVPN的安全性能。     

Structure synthesis and statics analysis of a foldable stair

This paper proposes a foldable stair that can be deployed for use and folded for conservation and investigates the geometry and statics of the structure. It not only has the moving flexibility of a mechanism but also has the high stiffness and high strength of statically indeterminate structures. The primary linkage is a deployable scissor-like element which forms the staircase after expanding. This paper starts with the analysis of the geometry of planar four- and six-bar mechanisms and processes to synthesize the foldable stair and then investigates its statics. The paper further investigates redundant inner forces of every link based on the second Castigliano theorem, develops a foldable stair model, assembles and manufactures. Working experiments verify the theoretical results and the outstanding advantages over the general fixed stairs.     

Authentication of the 31 species of toxic and potent Chinese materia medica by microscopic technique assisted by ICP-MS analysis, part 4: four kinds of toxic and potent mineral arsenical CMMs

Toxic and Potent Chinese Materia Medica (T/PCMM) is a special and very important category of Chinese medicines. They have long been used in traditional medical practice and are being used more and more widely throughout the world in recent years. As there may be many fatal toxic effects caused by misusing or confusion of T/PCMM, their quality and safety control arouse increasing attention internationally. Researches on the accurate identification to ensure the safe use of T/PCMM are acquired; however, there are few reports on authentication. We are carrying out a series of studies on 31 T/PCMM originating from plants, animals, minerals, and secreta. In our previous studies, we proved that modern microscopic authentication is a simple, fast, effective, low cost, and less toxic method for identifying animal, seed, and flower T/PCMM. In the present study, we focused on the authentication of four kinds of mineral arsenicals, including orpiment (mainly containing As₂S₃), realgar (mainly containing As₄S₄), arsenolite, and arsenic trioxide (mainly containing As₂O₃). We examined the macroscopic and microscopic characteristics of the above minerals and found that they all can be easily identified and authenticated by using light microscopy coupled with polarized microscopy. Moreover, the authentication results for arsenolite and arsenic trioxide are confirmed by ICP‐MS analysis. We are sure that the morphological and microscopic characteristics indicated here are indispensable to establishing standards for these four mineral T/PCMMs. Microsc. Res. Tech. 74:1‐8, 2011. © 2010 Wiley‐Liss, Inc.     

基于模糊决策的风力发电产业评价研究

根据风力发电技术产业的特点,构建改进层次分析与模糊一致矩阵相结合的方案决策数学模型,该模型既可以减少确定判断矩阵的盲目性,又可以避开评价体系中各等级间的隶属度确定问题,使评价结果更加可靠,适合于信息尚不完整、受主观因素影响较强的评价。实例验证了这一模型的合理性、可行性和有效性,具有实用价值。     

水库水中有机物特性对生成消毒副产物的影响

饮用水中消毒副产物( DBPs)对人体健康构成极大威胁,明确水源水中有机物的特性及对DBPs生成的影响,是实现DBPs有效源头控制的关键环节.研究探讨了上海某水库水源水中有机物不同组分与消毒副产物生成潜能之间的关系,为水处理工艺及饮用水安全保障技术研究提供基础性数据.结果表明,水样中亲水性有机物比例占到60％左右;各组分的相对分子质量分布情况以小于1 000的小分子为主;加强消毒前水处理工艺对亲水性和小分子有机物的去除,可以有效控制DBPs的生成.     

基于机器视觉的微片状物厚度检测

针对片状颗粒厚度检测的实际需求,结合机器视觉、图像处理和嵌入式技术,设计与实现了一套基于高性能ARM11的微片状颗粒厚度检测系统。该系统以QT和S3C6410为软硬件平台,提出了利用轮廓提取和最小矩形边界框相结合的方法计算片状颗粒厚度。结果表明,该检测系统具有处理速度快,测量精度高和成本低廉等优点,满足了对颗粒厚度测量的需求。     

Spatial variability of thermal regimes and other environmental determinants of stream fish communities in the Great Lakes Basin,Ontario, Canada

Temperature is one of the most important environmental variables in stream ecosystems because it affects the growth, survival and distribution of stream biota. This study examined if the spatial variability of thermal regimes and 18 other environmental variables were associated with fish communities in watersheds throughout the Great Lakes Basin (GLB), Ontario. The thermal regimes were defined as regimes 1, 2 and 3 and had maximum water temperatures of 26.4, 28.4 and 23.5°C, and spring warming rates of 0.20, 0.12 and 0.10 °C d^?1, respectively. The spatial variability of the thermal regimes (VTR) within the watersheds was summarized into four VTR groups: S1, S2, M23 and M123. Stream sites in S1 watersheds had temperatures characteristic of regime 1 whereas stream sites in S2 watersheds followed regime 2. M23 watersheds had sites with a mix of regimes 2 and 3 whereas M123 watersheds had all three thermal regimes at sites throughout watersheds. Canonical correspondence analysis (CCA) indicated that 16% of the variation in fish communities was related to the spatial VTR in the watersheds. Forward selection CCA indicated that elevation, the S1 VTR group, sparse forest cover, wetland area, base flow index (groundwater discharge potential), flow and industrial stress explained 42% of the variance in the fish communities. Simplified indicator species analysis (ISA) showed that different species could be used as indicators for each of the VTR groups. Human activities such as industrial development, deforestation, groundwater withdrawal and flow alteration all may affect the environmental variables related to stream fish communities. Copyright © 2010 John Wiley & Sons, Ltd.     

一种基于分段测量的Internet端到端性能参数估计方法

传统的基于测量的Internet性能参数估计要求测量点是端到端路径的起点和终点,这一方面使得测量和估计带有很大盲目性,增加了网络流量;另一方面会导致测量方法难于实施,估计结果不准确。提出了基于分段测量的思想,对ITU-T定义的延迟、延迟变化、丢包率和错误率4个参数进行测量和估计。由于测量是分段进行的,每次测量值都可应用于多条端到端路径的性能参数估计,因此降低了盲目性并大大减少了网络流量。为验证本方法的性能,基于PlanetLab平台设计和实现了生成器、性能参数测量机和结果收集器。通过在全球的100多个节点上的部署和为期一个月的运行证明了该方法便于实施,并且具有较高的准确性。     

SQL Server的数据库加密技术的研究与实现

数据库加密就是对数据库的文件或数据进行加密,数据加密后以密文方式存储,即使被窃取、被拷贝,机密数据也不会被敌对方获取。本文介绍了SQL Server数据库常见的安全问题和数据库加密技术,提出了一种对于数据库字段的加密技术。