校园计算机网络安全隐患与应对策略

目前,各学校都建成了一定规模的计算机网络,为教学、科研提供了很大的便利,但同时良莠不齐的信息、日益猖獗的黑客、林林总总的电脑病毒,给校园网带来极大的负面影响。本文分析了校园网存在的安全隐患,提出了加强网络安全的对策,以确保校园网安全稳定地运转,保障教学、科研的正常进行。     

校园网安全问题的分析与策略

校园网作为学校重要的基础设施，担任着学校教学、科研、管理、对外交流等重要任务。但是校园网的安全问题也日益突出。做好安全防范是当务之急。     

校园建筑网络综合布线系统方案设计

随着信息化校园的概念被各高校广泛接受,校园网的建设水平和应用程度已经成为衡量一个学校基础设施的重要标志。而校园网中综合布线系统建设的好坏,将关系到学校能否在教学、管理、科研的激烈竞争中占领制高点。简要分析了传统布线方案的不足之后,提出了针对校园网的实用的综合布线方案思想,对具体的各个重要环节进行详细的介绍,包括布线标准的选择与相应的线材材质挑选,在这个基础上进一步描述了综合布线方案的优先原则。最后结合实际应用经验介绍了布线工程中的关键注意事项。     

校园网防病毒体系建设

校园网是维持学校正常运转的基础,在网络规模和应用水平飞速发展的同时,各种病毒、木马、恶意软件对校园网的威胁也越来越大,如何保障校园网上信息系统的安全已经成为至关重要的问题。本文结合华东理工大学近几年在防病毒体系建设的工作经验,探讨了防病毒体系在校园信息化建设中的作用以及管理运行防病毒体系的一些体会和认识,并介绍了校园网防病毒体系在未来几年内的进一步规划。     

教学平台应注重校园网建设

随着高等教育的迅速发展,传统的教学模式已经不能适应教学的需要,教学平台的网络化使校园网在教学中的地位越来越重要,必须加强校园网的建设。     

网络教学促进教学现代化

进入21世纪随着计算机网络技术和Internet的不断发展,网络教学已经成为一种现实。所谓网络教学是指教师利用计算机网络向学生传递教学信息,或学生通过计算机网络获取学习的知识。不少学校顺应时代需要建设了校园网,并连入了互联网,开始了网络教学的尝试。开展网络教学有何意义?它对学校教学将会带来什么影响?当前开展网络教学应注意些什么?本文从教育者的角度想就这些问题作初步的探讨。1开展网络教学是信息时代的必然选择教育是一个产业,其产品的好坏需要社会的检验。当今社会信息量大,知识更新快,人才竞争激烈,网络教学就是信息时代的一…     

浅谈校园无线网络安全

随着笔记本电脑的普及,以及学校师生对无线上网的迫切要求,很多院校在原有有线校园网的基础上,通过有线加无线的方式,组建了校园无线网络。师生在享受无线网络自由与便利的同时,校园网也面临着新的安全威协。本文通过阐述校园无线网络所面临的安全威协,在分析校园无线网络安全的基础上,系统地阐述了应对校园无线网络所面临的威协应采取的安全技术措施。     

校园网络设计

科技的进步带来对学校教育的新要求—教育的现代化,资源的共享,完备的数据交换体系。本论文以某省一中校园网络建设的项目为例,介绍校园网络建设的目标、网络系统的设计等,对内综合了校园里的计算机资源,对外建立了快速传递数据信息的交换体系。     

仪器分析及实验网络课程建设与实践效果研究

为弥补仪器分析及实验传统教学的不足,基于校园网的moodle平台建设了仪器分析及实验网络课程,并采用网络课程与传统课堂教学相结合的混合教学方式开发了本门课程的设计与实践。教学实践证明,混合教学模式得到了学生的认可,学生的学习效率得到有效提高。     

信息化教学背景下无线校园网建设方案研究

面临网络技术的不断改变以及工作模式的改变,社会环境的变化趋势越发突出,这个简介提高了社会人才培养相关要求,建设校园网络已经成为高职院校所必须完成任务。对此,为了进一步提升无线校园网的整体建设效益,本文简要分析信息化教学背景下无线校园网建设方案,希望可以为相关工作者提供理论性帮助。     

Insect antifeedant properties of anthranoids from the genusVismia

Vismiones and ferruginins, representatives of a new class of lypophilic anthranoids from the genusVismia were found to inhibit feeding in larvae of species ofSpodoptera, Heliothis, and inLocusta migratoria.     

Direct observation of freeze-thaw instability of latex coatings via high pressure freezing and cryogenic SEM

Despite its industrial importance, the subject of freeze-thaw (F/T) stability of latex coatings has not been studied extensively. There is also a lack of fundamental understanding about the process and the mechanisms through which a coating becomes destabilized. High pressure (2100 bar) freezing fixes the state of water-suspended particles of polymer binder and inorganic pigments without the growth of ice crystals during freezing that produce artifacts in direct imaging scanning electron microscopy (SEM) of fracture surfaces of frozen coatings. We show that by incorporating copolymerizable functional monomers, it is possible to achieve F/T stability in polymer latexes and in low-VOC paints, as judged by the microstructures revealed by the cryogenic SEM technique. Particle coalescence as well as pigment segregation in F/T unstable systems are visualized. In order to achieve F/T stability in paints, latex particles must not flocculate and should provide protection to inorganic pigment and extender particles. Because of the unique capabilities of the cryogenic SEM, we are able to separate the effects of freezing and thawing, and study the influence of the rate of freezing and thawing on F/T stability. Destabilization can be caused by either freezing or thawing. A slow freezing process is more detrimental to F/T stability than a fast freezing process; the latter actually preserves suspension stability during freezing. Presented at the 82nd Annual Meeting of the Federation of Societies for Coatings Technology, October 27–29, 2004 in Chicago, IL. Tied for first place in The John A. Gordon Best Paper Competition.     

Ethanol and (−)-α-Pinene: Attractant Kairomones for Bark and Ambrosia Beetles in the Southeastern US

In 2002–2004, we examined the flight responses of 49 species of native and exotic bark and ambrosia beetles (Coleoptera: Scolytidae and Platypodidae) to traps baited with ethanol and/or (−)-α-pinene in the southeastern US. Eight field trials were conducted in mature pine stands in Alabama, Florida, Georgia, North Carolina, and South Carolina. Funnel traps baited with ethanol lures (release rate, about 0.6 g/day at 25–28°C) were attractive to ten species of ambrosia beetles (Ambrosiodmus tachygraphus, Anisandrus sayi, Dryoxylon onoharaensum, Monarthrum mali, Xyleborinus saxesenii, Xyleborus affinis, Xyleborus ferrugineus, Xylosandrus compactus, Xylosandrus crassiusculus, and Xylosandrus germanus) and two species of bark beetles (Cryptocarenus heveae and Hypothenemus sp.). Traps baited with (−)-α-pinene lures (release rate, 2–6 g/day at 25–28°C) were attractive to five bark beetle species (Dendroctonus terebrans, Hylastes porculus, Hylastes salebrosus, Hylastes tenuis, and Ips grandicollis) and one platypodid ambrosia beetle species (Myoplatypus flavicornis). Ethanol enhanced responses of some species (Xyleborus pubescens, H. porculus, H. salebrosus, H. tenuis, and Pityophthorus cariniceps) to traps baited with (−)-α-pinene in some locations. (−)-α-Pinene interrupted the response of some ambrosia beetle species to traps baited with ethanol, but only the response of D. onoharaensum was interrupted consistently at most locations. Of 23 species of ambrosia beetles captured in our field trials, nine were exotic and accounted for 70–97% of total catches of ambrosia beetles. Our results provide support for the continued use of separate traps baited with ethanol alone and ethanol with (−)-α-pinene to detect and monitor common bark and ambrosia beetles from the southeastern region of the US.     

Methyl 2,4,6-decatrienoates Attract Stink Bugs and Tachinid Parasitoids

Halyomorpha halys (Stål) (Pentatomidae), called the brown marmorated stink bug (BMSB), is a newly invasive species in the eastern USA that is rapidly spreading from the original point of establishment in Allentown, PA. In its native range, the BMSB is reportedly attracted to methyl (E,E,Z)-2,4,6-decatrienoate, the male-produced pheromone of another pentatomid common in eastern Asia, Plautia stali Scott. In North America, Thyanta spp. are the only pentatomids known to produce methyl 2,4,6-decatrienoate [the (E,Z,Z)-isomer] as part of their pheromones. Methyl 2,4,6-decatrienoates were field-tested in Maryland to monitor the spread of the BMSB and to explore the possibility that Thyanta spp. are an alternate host for parasitic tachinid flies that use stink bug pheromones as host-finding kairomones. Here we report the first captures of adult and nymph BMSBs in traps baited with methyl (E,E,Z)-2,4,6-decatrienoate in central Maryland and present data verifying that the tachinid, Euclytia flava (Townsend), exploits methyl (E,Z,Z)-2,4,6-decatrienoate as a kairomone. We also report the unexpected finding that various isomers of methyl 2,4,6-decatrienoate attract Acrosternum hilare (Say), although this bug apparently does not produce methyl decatrienoates. Other stink bugs and tachinids native to North America were also attracted to methyl 2,4,6-decatrienoates. These data indicate there are Heteroptera in North America in addition to Thyanta spp. that probably use methyl 2,4,6-decatrienoates as pheromones. The evidence that some pentatomids exploit the pheromones of other true bugs as kairomones to find food or to congregate as a passive defense against tachinid parasitism is discussed.     

2005～2006年国外塑料工业进展

收集了2005年7月～2006年6月国外塑料工业的相关资料，介绍了2005—2006年国外塑料工业的发展情况。提供了世界塑料产量、消费量及全球各类树脂生产量以及各国塑料制品的进出口情况。作为对比，介绍了中国塑料的生产情况。按通用热塑性树脂（聚乙烯、聚丙烯、聚苯乙烯、聚氯乙烯、ABS树脂）、工程塑料（聚酰胺、聚碳酸酯、聚甲醛、热塑性聚酯、聚苯醚）、通用热固性树脂（酚醛、聚氨酯、不饱和树脂、环氧树脂）、特种工程塑料（聚苯硫醚、液晶聚合物、聚醚醚酮）的品种顺序，对树脂的产量、消费量、供需状况及合成工艺、产品开发、树脂品种的延伸及应用的扩展作了详细的介绍。     

2007～2008年世界塑料工业进展

收集了2007年7月～2008年6月世界塑料工业的相关资料,介绍了2007～2008年国外塑料工业的发展情况,提供了世界塑料产量、消费量及全球各类树脂的需求量及产能情况.按通用热塑性树脂(聚乙烯、聚丙烯、聚苯乙烯、聚氯乙烯、ABS树脂)、工程塑料(尼龙、聚碳酸酯、聚甲醛、热塑性聚酯、聚苯醚)、特种工程塑料(聚苯·硫醚、液晶聚合物、聚醚醚酮)、通用热固性树脂(酚醛、聚氨酯、不饱和聚酯树脂、环氧树脂)不同品种的顺序,对树脂的产量、消费量、供需状况及合成工艺、产品应用开发、树脂品种的延伸及应用的进一步扩展等技术作了详细介绍.