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本文介绍了网络信息安全面临的主要威胁;分析了网络安全存在的隐患;论述了计算机网络安全的内容;介绍了网络使用的主要安全技术、防火墙技术、加密技术、入侵检测技术;提出了加强网络和系统安全的措施。 相似文献
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由于网络技术的迅速发展,导致网络空间安全问题变得更加复杂化,各种类型的网络攻击严重威胁着用户的隐私安全。为解决传统网络安全的静态控制防护、被动防护问题,提高网络安全防御能力,根据新型网络安全要求,提出了一种基于大数据技术的网络安全态势感知平台设计方案。首先简单对网络态势感知进行了概述,其次对该平台的架构以及功能模块进行设计,并建立了针对网络安全威胁的动态防御体系和安全监控体系,提高了网络安全防御水平,降低了网络安全风险,最后通过测试证明设计的网络安全态势感知平台在应用中的可行性。 相似文献
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从系统安全角度出发,安全仪表系统的性能评估应尽可能的覆盖各种安全功能失效。本文基于不同使用阶段的安全功能失效,建立了安全仪表系统的性能评估方法。根据安全仪表系统使用过程中的特点,该方法综合考虑了安全仪表系统在被动休眠期、过程要求时和维修测试期内可能发生的系统安全功能失效,并分别进行定量,最后给出了安全仪表系统的整体安全功能失效模型。应用实例表明该方法更加详尽合理。 相似文献
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ZHAO Fei ZHU Boquan LI Xiangcheng ZHU Yuenan 《中国耐火材料》2014,(3):31-34
The basic formulation of Al2O3- C slide plates was65%( in mass,the same hereinafter) white fused corundum particles,25% white fused corundum fines,6% active α-Al2O3 micropowder,4% carbon black and flake graphite, and additional 4% phenolic resin.Based on this formulation,3% Al powder,3% Si powder,and 3% Al + 3% Si powder were used to substitute equivalent white corundum fines to improve the hot mechanical properties of Al2O3- C slide plates. The specimens with dimensions of 140 mm × 25 mm × 25 mm were pressed at 150 MPa,dried at 200 ℃ for 24 h,and hot treated at 1 400 ℃ for 3 h in carbon embedded condition. Then hot modulus of rupture and thermal shock resistance of the specimens were tested and the phase compositions and microstructure were analyzed. The results show that specimen with 3% Al powder has the higher hot modulus of rupture but lower residual modulus of rupture after thermal shock than the specimen with3% Si powder; the specimen with 3% Al + 3% Si powders exhibits the highest hot modulus of rupture and the best thermal shock resistance; the change of mechanical property is closely related with the in-situ formed nonoxides: AlN in the form of bars is formed in specimens with Al powder; fibrous SiC whiskers are formed in specimens with Si powder; in the specimens with both Al and Sipowders,besides AlN and SiC whiskers,hexagonal tabular SiAlON is in-situ synthesized,which interlocks with each other. 相似文献
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现今流行的一些书籍、期刊杂志、广告、招贴、网页等,已看不到长篇累牍的枯燥文字,取而代之的是用大量生动、吸引人的图片、插图、版式以及视觉整体设计来表达内容。一些设计精良的图书,“图文”各占的比例正在偏向“图”,真正做到了”图文并茂”。这种设计方式正在成为人们喜闻乐见的形式。计算机技术的飞速发展,印刷系统的各种新形式,软件的开发利用,以及网络技术、多媒体技术的应用等,更使大众传媒的视听表现获得了前所未有的创造空间。 相似文献
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The nanoporous thermal insulating material was prepared by using fumed silica,SiC powder and glass fiber as starting materials,the appropriate thickness of the nanoporous thermal insulating material lined in ladle was discussed by the simulation method,and the effect of its application as ladle lining was investigated.The results show that the thermal conductivity of the nanoporous thermal insulating material prepared in composition of fumed silica: SiC powder: glass fiber =75: 20:5 (in mass) is 0.023 W · m^-1 · K^-1 at 1 000 ℃,the appropriate thickness of the nanoporous thermal insulating material lined in ladle is ≤ 5 mm and the average temperature of the ladle outside surface when lined with the nanoporous thermal insulating material is 95 ℃ lower than that with the ordinary thermal insulating material. 相似文献
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软件体系结构设计方法越来越受到研究者和实践者的重视,本文概述了软件体系设计方法主要分类,分析了非功能需求及用例技术的作用。详细阐述了使用UCGD方法进行软件体系结构设计的步骤,结合鲁棒性分析等技术,探讨了UCGD多个方面的改进,在计算机围棋系统架构中进行了初步尝试。 相似文献
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嵌入式系统IAP在GPRS远程集中抄表系统中的应用 总被引:1,自引:0,他引:1
介绍IAP(在应用编程)方法及其相关应用,以及将IAP应用于嵌入式系统设备软件远程升级的现实意义;结合某地区远程集中抄表系统,着重阐述采用GPRS无线通信进行远程软件升级的思想和实现方法,以及应用中应注意的一些关键技术,并讨论了提高GPRS远程升级速度和可靠性的一些措施。 相似文献
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介绍有关概念教学的重要性及在概念教学中重视培养学生的思维能力、概念教学过程中应注意的问题和概念教学中采取的包括淡化、浅化、深化、跨越,在概念教学中应注意的问题, 相似文献
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This review summarized the recent advances in the utilization of nonmetallic minerals and their applications for fabrication of unfired refractories.The preparation of refractory powder utilizing cheap nonmetallic minerals of zircon,low-grade bauxite and quartz was discussed,respectively.The preparation of three unfired SiC-based refractories:SiC-SiAlON-ZrN,Al2O3-SiC/β-SiAlON/Ti(C,N)-C,and Al2O3-SiC-Si3N4 using the as-prepared refractory powders was introduced. 相似文献
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In order to prolong the service life of castables for hot blast stove pipes,effects of SiO2 micropowder addition and aggregate kind on properties of castables for hot blast stove pipes,and properties of silica sol bonded castables were researched using homogenized bauxite,andalusite particles,andalusite fines,white fused corundum fines,α-Al2O3 micropowder,pure calcium aluminate cement,SiO2 micropowder,and silica sol as starting materials. The results show that:(1) as SiO2 micropowder addition increases,the shrinkage rate of fired specimens increases; BD increases firstly,reaches the highest at 4 mass%,and then decreases; CMOR and CCS of all specimens increase gradually; so the appropriate SiO2 micropowder addition is 4 mass%;(2) the specimens with bauxite aggregate have better CCS and volume stability,but specimens with andalusite aggregate have better thermal shock resistance;( 3) for castables for hot blast stoves using silica sol as binder,the addition of pure calcium aluminate cement can decrease the linear change rate after treatment at 1 400℃ and can slightly enhance CCS and CMOR,but has very little influence on AP and BD; and the introduction of citric acid worsens the thermal shock resistance of specimens. 相似文献