基于智能流量预测的入侵检测方法

为了提高入侵检测系统检测的实时性,提出了一种基于智能流量预测的入侵检测方法。该方法拟合了智能Agent的智能性、自主性和自适应性的优点以及灰色预测对不确定资源的科学预测的优点,用流量预测智能Agent预测得到的流量序列来代替未来一段时间段内的实际流量,并把这个预测序列作为检测对象集的一部分。然后用人工方法模拟了流量处理Agent与预测智能Agent的活动,并通过对实际的采集数据进行仿真,实验证明了预测智能Agent的预测活动的科学性。     

溢洪道底板空蚀发生位置及抗空蚀措施分析

以肯斯瓦特水利枢纽工程为例,通过水工模型试验,测试其设计水位工况下和泄洪消能标准水位工况下溢洪道泄洪时底板的流速及压力分布,并根据空化理论模型对其底板沿程空化数进行了计算。结果表明:可以通过溢洪道流速特性和底板压力分布来分析过流面的空化空蚀特点;在实际工程中,可采用优化过流面的体形、设置掺气减蚀设施、控制溢流面的不平整度以及使用抗空蚀材料等方法来防止空化和空蚀的发生。     

渠道工程中保温板防冻胀设计

我国北方大部分地区都属于季节性冻土地区,输水渠道经常会由于地基的冻胀而遭到不同程度的破坏。目前虽有不少地区的输水渠道采用了聚苯乙烯保温板防冻胀措施,而且取得了一定的效果,但聚苯乙烯保温板防冻胀设计还处在初级阶段。提出渠道工程中保温板防冻胀的设计方法,首先介绍了聚苯乙烯保温板的物理、力学以及冻融循环特性;然后论述了干燥和湿润状态下如何选取保温板厚度;最后结合工程实例说明了设计过程。对同类工程的设计有参考借鉴意义。     

流域初始水权分配方法与模型

针对初始水权的分配问题,分析了目前两种主要分配机制———计划与市场的原理和模型及其不足,将拍卖方式引入初始水权配置,建立初始水权的拍卖模型;以玛纳斯河流域为例,分析了流域初始水权配置的现状及存在的问题,最后给出流域初始水权配置新的思路,为干旱内陆河流域初始水权配置提供理论基础.     

混凝土搅拌车搅拌叶片优化设计

混凝土搅拌车叶片是实现搅拌筒功能的主体结构,具有搅拌和出料功能。在分析搅拌叶片总体结构的基础上,介绍了前锥、圆柱段、后锥各部螺旋叶片的设计特点及设计方法,提出了新的改进措施,并运用Pro/E软件建立螺旋叶片三维模型,进行有限元分析。改善了叶片结构性能,提高了使用寿命和工作效率,为搅拌叶片的结构改进设计提供了参考依据。     

Tailoring the bandgap of N-rich graphitic carbon nitride for enhanced photocatalytic activity

Nitrogen - rich graphitic carbon nitride (Ng-C₃N₄) with improved photocatalytic activity was engineered using a facile post-annealing treatment of pristine g-C₃N₄ in N₂ atmosphere. The thermal annealing did not modify the crystal structure, vibrational modes, or morphology of the N-rich g-C₃N₄ (Ng-C₃N₄). However, it decreased the crystallinity by broadening the dominant X-ray diffraction (XRD) peak and increased the surface area and mesoporous nature because of the formation of carbon vacancies. Diffuse reflectance spectroscopy indicated that the bandgap of the annealed Ng-C₃N₄ decreased from 2.82 to 2.77 eV compared to pristine g-C₃N₄. The increase of nitrogen content in the annealed Ng-C₃N₄ was quantified by X-ray photoelectron spectroscopy (XPS), which was also used to examine the formation of carbon vacancies. Photocurrent and electrochemical impedance spectroscopy measurements showed that the annealed Ng-C₃N₄ had higher light absorption capacity than the pristine g-C₃N₄. The photocatalytic performance of the samples was investigated for the degradation of crystal violet (CV) under ultra-violet light irradiation. The annealed Ng-C₃N₄ sample exhibited superior photodegradation of CV over pristine g-C₃N₄.     

木糖制备过程研究

文章对生产木糖的主要原料、主要工艺及木糖功用进行了综述，并提出利用农产品废弃物制备木糖工业生产的展望。     

Spherical activated carbon as an enhanced support for TiO2/AC photocatalysts

Titanium dioxide nanoparticles prepared in situ by sol–gel method were supported on a spherical activated carbon to prepare TiO₂/AC hybrid photocatalysts for the oxidation of gaseous organic compounds. Additionally, a granular activated carbon was studied for comparison purposes. In both types of TiO₂/AC composites the effect of different variables (i.e., the thermal treatment conditions used during the preparation of these materials) and the UV-light wavelength used during photocatalytic oxidation were analyzed. The prepared materials were deeply characterized (by gas adsorption, TGA, XRD, SEM and photocatalytic propene oxidation). The obtained results show that the carbon support has an important effect on the properties of the deposited TiO₂ and, therefore, on the photocatalytic activity of the resulting TiO₂/AC composites. Thus, the hybrid materials prepared over the spherical activated carbon show better results than those prepared over the granular one; a good TiO₂ coverage with a high crystallinity of the deposited titanium dioxide, which just needs an air oxidation treatment at low-moderate temperature (350–375 °C) to present high photoactivity, without the need of additional inert atmosphere treatments. Additionally, these materials are more active at 365 nm than at 257.7 nm UV radiation, opening the possibility of using solar light for this application.