Quantitative method for network security situation based on attack prediction

To predict the attack behaviors accurately and comprehensively as well as to quantify the threat of attack,a quantitative method for network security situation based on attack prediction was proposed.By fusing the situation factors of attacker,defender and network environment,the capability of attacker and the exploitability rate of vulnerability were evaluated utilizing the real-time detected attack events,and the expected time-cost for attack-defense were further calculated.Then an attack prediction algorithm based on the dynamic Bayesian attack graph was designed to infer the follow-up attack actions.At last,the attack threat was quantified as the security risk situation from two levels of the hosts and the overall network.Experimental analysis indicates that the proposed method is suitable for the real adversarial network environment,and is able to predict the occurrence time of attack accurately and quantify the attack threat reasonably.     

改性锦纶短纤维在高性能轿车子午线轮胎胎面胶中的应用

研究改性锦纶短纤维在高性能轿车子午线轮胎胎面胶中的应用。结果表明:改性锦纶短纤维替代部分炭黑后,混炼胶的硫化速度加快,焦烧时间缩短;硫化胶的密度减小,压缩疲劳温升降低,60℃的损耗因子(tanδ)减小,撕裂强度增大,但拉伸强度和耐磨性能有所下降,且变化趋势随着改性锦纶短纤维用量的增大而增大。采用6份改性短纤维替代4份炭黑用于胎面胶配方,胶料的温升降低1~2℃,60℃的tanδ值减小;成品轮胎的高速和耐久性能均提高,滚动阻力降低。     

复合衬里在半水法磷酸萃取槽防腐上的应用

介绍半水法磷酸萃取槽腐蚀方案设计及对比,提出隔离层采用氯化丁基复合橡胶板,防腐层采用呋喃树脂胶泥衬碳板。实际使用表明,该复合衬里技术具有很好的成本优势,现场施工简单,运行周期长,维修频率低。     

光纤环温度性能分析软件设计

介绍了影响光纤陀螺温度性能的主要因素—Shupe效应,论述了基于LabVIEW软件设计开发的光纤环温度性能分析软件的程序组成和功能,并利用光纤环温度性能分析软件开展了内外热源两种工作条件下,光纤陀螺温度性能的仿真分析及与光纤陀螺测试结果的对比评价。结果表明,仿真分析结果与光纤陀螺测试结果一致,光纤环温度性能仿真分析软件能够将光纤环有限元分析结果与光纤陀螺输出有机结合。     

湿式静电除尘器喷嘴特性

为优化湿式静电除尘器清灰特性,研究喷嘴特性.采用相位多普勒粒子分析仪(PDA),研究单喷嘴、双喷嘴同轴侧向撞击及喷嘴与壁面碰撞后的雾化特性,实验数据表明液滴撞壁后形态主要由液滴自身动能、液滴表面张力和黏度决定,由韦伯数描述.距离喷嘴位置越远,喷嘴雾化角越大,索特尔平均粒径(SMD)波动越小,韦伯数分布越均匀,液膜均布性越好.在此基础上,对喷嘴布置方式与液膜均布性关系做进一步分析,得到喷淋管间距越大,喷嘴角度越大,极板上水膜更加均匀,该实验结果与喷嘴特性实验相符.     

固定化基因工程菌的培养和hEGF表达

引　言人表皮生长因子 (humanepidermalgrowthfactor,hEGF)是由 5 3个氨基酸残基组成、相对分子质量为 6 0 4 5的单链多肽[1] .hEGF具有多种生物活性 ,并在医药、化妆品工业中具有广泛用途 .国内外已有很多重组表达hEGF的报道[2 ,3] .但是 ,各种hEGF表达系统的质粒稳定性随培养     

利用乙酰丙酸合成双酚酸的工艺研究

研究了以苯酚和新型平台化合物乙酰丙酸为原料,采用盐酸为催化剂、巯基乙酸为助催化剂催化合成高分子材料单体双酚酸的合成工艺.考察了助催化剂种类及用量、反应物料配比、反应温度、反应时间和催化剂用量对双酚酸产率的影响.研究结果表明,巯基乙酸可以作为助催化剂有效地促进乙酰丙酸和苯酚的缩合,用量为n[巯基乙酸]:n[乙酰丙酸]为0.02,n[HCl]∶n[乙酰丙酸]为4,n[苯酚]∶n[乙酰丙酸]为4,反应温度60℃,反应时间40 h.在该条件下,双酚酸的产率为97.1%.产物进一步经红外光谱、氢核磁谱进行表征,证实为双酚酸.     

电沉积Ni–Ru合金及其结构和性能研究

在(25±2)°C下,从含有50g/LRuCl3·nH2O、30.0g/L乙酸钠、30.0g/L二水合柠檬酸钠和15.0~50.0g/LNiSO4·6H2O的溶液(pH3.0)中,以10~90mA/cm2在铜基底上电沉积制备了Ru含量为5%~70%(原子分数)的Ni–Ru合金。采用X射线衍射(XRD)、扫描电子显微镜(SEM)和电化学方法,研究了镀液中NiSO4质量浓度和电流密度对沉积层组成、表面形貌、结构及电催化析氢活性的影响。结果表明,溶液中Ru优先析出并能促进Ni的沉积,镀层中Ru含量随着镀液中Ni2 质量浓度的提高而降低,低电流密度有利于获得Ru含量高的镀层。随着镀液中Ni2 质量浓度的降低或电流密度的提高,镀层表面形貌由较为平整、均匀变为多孔的颗粒状。镀层主要呈现面心立方Ni结构特征,且晶粒尺寸随镀层中Ru含量的增加而变小。Ni–Ru合金电极的析氢活性优于纯Ni,当镀层的Ru原子分数超过15%时,其析氢活性与纯Ru电极接近。     

Numerical Investigation of a New Method for Reducing Bends Erosion from Particles Impacts

The present paper intends to introduce a new method for reducing bends erosion from particles impacts: the ribbed bend erosion protection method. Ribs are evenly fixed in the range of 20°-80° on the inner-wall of inside 90?bend and the bend (including ribs) is made of medium carbon steel. Three-dimensional numerical work is performed and the result shows satisfactory agreement with the experimental measurement. Numerical simulation studies the characteristics of axial gas flow along the bend and secondary flow at cross section. Detailed analyses involving the impact velocity and incidence angle of particle-metal (either particle-rib or particle-duct) impact unveil the mechanism of the anti-erosion effect. As a result, predications achieve that the average erosion rate of the ribbed bends is only a third of the bare bend under test conditions and rectangle ribs possess higher anti-erosion effect than square ribs, while the wear distribution pattern remains unchanged after adding ribs onto the bend. All     

铁矿烧结过程料饼表面的散热行为研究

通过分析铁矿烧结过程料饼表面散热的机理,给出了散热量的计算方法,并且针对一台铁矿烧结机的料面温度、料面散热量和料饼热量缺失进行了测定研究.结果表明,料面温降、料面散热及其对料饼热量缺失的影响主要发生在0～5 min,在烧结料饼移出点火保温炉时,料面散热对于烧结料饼热量缺失的影响为46%,料面温降速度最大值达267℃/min,足以引起表层烧结矿的生烧或玻璃化;尽管料面散热在烧结能耗中所占比例不大,但对于烧结机的产量、烧结矿的质量和烧结工序的能耗均能产生一定的影响.