包裹型Al(OH)3-Y(OH)3/ZrB2复合粉体的合成工艺优化研究

本文采用共沉淀法优化包裹型Al(OH)3-Y(OH)3/ZrB2复合粉体的合成工艺,通过TEM对合成的复合粉体进行形貌分析,得出适宜的包覆工艺参数分别是pH=9、溶液浓度为Al3+=0.017 moL/L和Y3+ =0.01 mol/L、滴定速度为0.05 ml/s、反应时间为60min.通过优化工艺,可以合成出包裹结构较好的包裹型Al(OH)3-Y(OH)3/ZrB2复合粉体,其包裹层厚度约为150 ～ 300 nm,为改善ZrB2基复合材料难于烧结致密化和高温条件下易氧化奠定原料基础.     

优先权排队在消防物联网中的应用

针对消防物联网系统中消防监控中心收到的火警信息存在延迟,可能导致救火作战时机延误的问题,提出了一种火警信息优先传输的解决方案。首先,推导出FCFS的M/M/1排队系统的运行指标;其次,将消防报警信息分为火警报警信息、火警消除信息、故障报警信息和故障消除信息等四个优先级,建立非抢占优先权排队系统,并推导出各个优先级的运行指标;最后,从平均逗留时间和平均队长两个维度,比较了非抢占优先权排队系统和M/M/1系统的性能。提出的火警信息优先传输方案,满足了火警信息时延小的要求,同时实现复杂度低,为消防物联网安全信息数据的获取提供一定的理论支撑。     

线性代数CAI课件的研制及其启迪

本文作者结合线性代数CAI课件的开发,论述了该课件开发的依据、课件脚本编写的原则,并较详尽地介绍了《线性代数辅导课》系统的结构与功能。简述了作者对CAI的认识,指出了实行CAI的必要性和目的。     

Secondary Buckling Analysis of Thin Rectangular Plates Based on the Wavelet Galerkin Method北大核心CSCD

Application of the wavelet Galerkin method (WGM) to numerical solution of nonlinear buckling problems was studied with classical elastic thin rectangular plates. First, the discretized scheme of the von Kármán equation were introduced, then a simple calculation approach to the Jacobian and Hessian matrices based on the WGM was proposed, and the wavelet discretized scheme-based eigenvalue equation method, the extended equation method and the pseudo arc-length method for nonlinear buckling analysis were discussed. Second, the secondary post-buckling equilibrium paths of elastic thin rectangular plates and the effects of aspect ratios, boundary conditions and bi-directional compression on the mode jumping behaviors, were discussed in detail. Numerical results show that, the WGM possesses good convergence for solving buckling loads on rectangular plates, and the obtained equilibrium paths are in good agreement with those from the stability experiments, the 2-step perturbation method and the nonlinear finite element method. Given the feasibility of combination with different bifurcation computation methods, the WGM makes an efficient spatial discretization method for complex nonlinear stability problems of typical plates and shells. © 2023 Editorial Office of Applied Mathematics and Mechanics. All rights reserved.     

发泡剂含量对YAG多孔陶瓷的性能影响研究

采用共沉淀法合成YAG粉体,经过配料、干压成型和真空烧结制备YAG多孔陶瓷材料,并研究发泡剂含量对YAG多孔陶瓷的性能影响.结果表明:YAG多孔陶瓷随着发泡剂含量逐渐增多,其气孔率逐渐增高,抗压强度逐渐降低.烧结温度升高,气孔率下降,抗压强度升高.保温时间延长,气孔率降低,抗压强度升高,但是YAG多孔陶瓷的性能对于烧结温度和保温时间而言,烧结温度相对更为敏感.综合整个烧结工艺及性价比,YAG多孔陶瓷发泡剂含量为15wt;并在1550℃烧结保温lh较为适宜.