二维模型试验的数字摄影及其数据处理

模型试验中常用物理或机械的方法测量位移,该文利用数字近景摄影测量方法对位移进行了测量,并对位移的发生做了假设检验,极大地降低了将由误差引起的位置变动看作发生位移的概率。最后对边坡滑移的物理模型试验进行了位移量测。     

基于SOM神经网络的内燃机故障智能诊断研究

SOM神经网络是一个由全连接的神经元阵列组成的无教师自组织、自学习网络,它具有很强的非线性映射能力和柔性网络结构以及高度的容错性和鲁棒性.通过反复多次迭代训练,使之对训练样本形成科学合理的分类,然后利用此网络结构对待测样本进行实例仿真检验,判断此设备是否处于异常状态,从而可对设备的运行状态进行实时监测与智能诊断.实际算例也表明了该理论在内燃机智能故障诊断中的有效性及实用性.     

The steric effect of exfoliation agent for fabrication of layer niobium oxide nanosheet

In this research, the steric effect of an exfoliation agent between n-ethylamine and triethylamine for the fabrication of Ca₂Nb₃O₁₀⁻ nanosheet was investigated. The experimental results revealed that the different structures of the exfoliation agent have affected to fabrication of Ca₂Nb₃O₁₀⁻ nanosheet. The use of n-ethylamine as an exfoliation agent gave a maximum exfoliation efficiency of 10 wt.% while the maximum exfoliation efficiency of triethylamine was 90 wt.%. The result showed that the difference in exfoliation efficiency was caused by the steric effect of exfoliation agents. The image of transmission electron microscopy exhibited Ca₂Nb₃O₁₀⁻ nanosheets which were formed by exfoliation of HCa₂Nb₃O₁₀. Furthermore, the reaction time for liquid exfoliation was studied in this work. The reaction time at 4 h gave a maximum of exfoliation efficiency. The Ca₂Nb₃O₁₀⁻ suspension was tested capability to remove hazardous ions. After the experiment, we found the white precipitate which was the formation of CsCa₂Nb₃O₁₀. The result showed that the Ca₂Nb₃O₁₀⁻ nanosheet was efficient for the removal of Cs⁺ ions in the wastewater.     

紫外光辐照交联聚氯乙烯的研究

研究了聚氯乙烯(PVC)在增塑剂邻苯二甲酸二辛酯(DOP)存在的情况下,以二苯甲酮(BP)为光敏剂、三丙烯酸三羟甲基丙烷酯(TMPTA)为交联剂的紫外光辐照交联。实验证明:光敏剂对交联有着显著的影响;经过辐照,可大幅度提高PVC制品的硬度及拉伸强度。     

Core‐shell structured Al/PVDF nanocomposites with high dielectric permittivity but low loss and enhanced thermal conductivity

Surface modification of core‐shell structured Al (Al@Al₂O₃) nanoparticles was performed using γ‐(Aminopropyl)‐triethoxysilane (APS) and dopamine (DA), respectively, and the microstructures, dielectric properties and thermal conductivities of the Al/poly(vinylidene fluoride) (PVDF) nanocomposites were investigated. Both DA and APS enhance the interfacial bonding strength between the fillers and the matrix, leading to homogeneous dispersion of Al nanoparticles in PVDF matrix. Compared with raw Al nanoparticles, surface‐treated Al/PVDF exhibit much higher dielectric permittivity due to the enhanced interfacial interactions between the two components, whereas, the dielectric loss and electric conductivity of the nanocomposites still remain at rather low levels owing to the insulating alumina shell preventing effectively core Al from direct contact. The dynamic dielectric properties results reveal that dielectric constant and loss increase with temperature due to the gradually enhanced mobility of molecular chain segments of PVDF for the raw Al/PVDF and treated Al/PVDF nanocomposites. Additionally, the PVDF nanocomposites with Al treated with APS and DA show enhanced thermal conductivities compared with raw Al/PVDF under the same filler loading because of reduced thermal interfacial resistance promoting phonon transfer across the interfaces. POLYM. ENG. SCI., 59:103–111, 2019. © 2018 Society of Plastics Engineers     

10kV配电站计算机监控系统的电气设计

以某公司10 kV配电站设计为例,介绍了10 kV配电站计算机监控系统的选型、继电保护、操作电源的设计,以及测量回路、信号回路、控制回路、中央信号系统、计算机网络的设计方法和应具备的功能.实践证明,设计方案可行,运行稳定.     

纳米TiO_2—两性淀粉对脱墨浆新闻纸抄造过程中DCS去除的研究

研究了两性淀粉(AmS)、纳米TiO2单元体系、纳米TiO2-AmS双元体系、阳离子淀粉(CS)/阳离子聚丙烯酰胺(CPAM)/阴离子聚丙烯酰胺(APAM)三元体系对全脱墨浆(DIP)的动态絮聚作用,并考察这几种助留助滤体系在白水循环使用情况下,对抄造纸页部分性能及白水中DCS去除效果的影响.动态絮聚实验表明:AmS单元体系几乎没有去除DCS的作用,增大用量还会使体系的DCS残留量更高;纳米TiO2单元体系有一定的DCS去除效果; TiO2-AmS双元体系不仅提高了DCS的去除效果,还降低试剂用量,当其用量为0.16%(TiO2)-0.4%(AmS)时,DCS的去除率达到50%以上;三元体系的助留助滤效果较好,但是DCS的去除效果一般.白水循环使用抄纸实验表明:纳米TiO2-AmS体系对残余油墨的捕集能力最强,对DCS的去除效果也最好,在白水循环抄纸进行到22次时,DCS的富集量达到平衡,白水离心处理后CODCr值为43 mg/L左右,较好抑制了DCS的进一步富集;三元体系在循环进行到52次时,其离心处理后白水CODCr值稳定在65 mg/L左右.     

Simulation of Microstructure for Hot Pack-Forging of a High Nb Containing TiAl Alloy

利用Deform-3D软件对高铌TiAl合金包套锻造过程中的微观组织演变进行模拟。为得到模拟所需参数,在1100～1250℃和0.001～0.5 s-1的条件下对合金进行了热压缩试验。在所得试验数据的基础上,利用一种间接方法建立了合金的动态再结晶模型,并利用Avrami形式的方程对再结晶分数进行描述。采用Cingara硬化模型及所建立的再结晶分数模型构建了合金的流变应力本构模型。模拟结果显示,由于锻造过程中摩擦的存在、热量的损失以及简单单向镦粗变形的锻造方式,使得坯料中的微观组织分布不均匀。通过模拟结果与实验结果的比较,证明所建立的有限元模型能够有效地预测高铌TiAl合金在包套锻造过程中的组织演变。     

酯固化碱性酚醛树脂粘结剂及其固化机理的研究

研究了酯固化碱性酚醛树脂的合成工艺，得到了高强度的粘结剂；分析了硅烷偶联剂对粘结强度的影响，并对酯的固化机理作了初步探讨。     

Soldering of Zr-based bulk metallic glass and copper by Au-12Ge eutectic alloy

Zr-based bulk metallic glass and copper with different surface roughness were soldered using low temperature eutectic Au-12 Ge(wt%) solder on a thermomechanical simulator. The cross-sectional microstructures of the brazed joints were analyzed by scanning electron microscopy(SEM) and transmission electron microscope(TEM) in detail, and the compositional distribution along the interface was analyzed by energy-dispersive spectrometer(EDS). Results show that the surface roughness of base metals plays an important role in the quality of the brazed joint because the surface roughness can enlarge the effective contact area, which can improve the brazing surface quality between two materials. A moderate roughness of treated Zr-based metallic glass of 18 μm is shown to be the best for the soldering, while the surface roughness has a weak effect on the soldering behavior of Au-12 Ge solder on copper. After soldering, long-range diffusion of atoms occurs between the base metal and solder, and five distinct regions are formed at the joint region.