磁性硅铁载铜吸附Hg0动力学机制及密度泛函研究

采用粉末冶金法将纳米单质铜(Cu⁰)、硅铁(FeSi)、四氧化三铁硅涂层(Fe₃O₄@SiO₂)混合煅烧并制备出新型磁性硅铁载铜吸附剂MagFeSi-Cu⁰。实验研究不同烟气温度下MagFeSi-Cu⁰的汞吸附能力基础上,结合颗粒内扩散模型、准二阶动力学模型、Elovich模型及Bangham模型分析了MagFeSi-Cu⁰吸附Hg⁰过程的主要控制步骤。在此基础上,依据密度泛函理论(DFT)研究了不同反应温度下FeSi表面Cu⁰原子与Hg⁰原子的汞齐作用机制。研究结果表明,Bangham模型的拟合值与MagFeSi-Cu⁰汞吸附实验值拟合度最高,MagFeSi-Cu⁰表面痕量Hg⁰吸附由汞的外扩散和表面铜汞齐吸附共同控制;通过密度泛函计算,发现Cu⁰颗粒表面Cu-Hg齐吸附能为-0.534 eV,当烟气温度从80℃上升至200℃时,Hg⁰原子与单质Cu原子的吸附自由能从-22.47 kJ/mol下降至-13.96 kJ/mol,这些结果为深入了解Hg⁰在Cu(111)表面的反应机理提供了理论基础。     

振动监测系统的可调增益技术与实现

文章设计了一种具有可调增益功能的振动监测系统。首先从监测层和测量层两个方面提出了振动监测系统的整体框架,之后给出了硬件系统和软件系统的设计方法及软件实现代码,利用控制芯片和可调增益放大器,在监测系统中整合了一套可根据采集信号幅值大小调整增益的数据采集装置;利用模拟信号发生器对不加增益和设置可调增益之后的两种信号进行了对比分析,并在汽轮发电机组实际工况下进行了振动信号采集。结果表明,具备可调增益功能的振动监测系统可有效提高采集信号的信噪比,提高汽轮发电机组的振动监测能力。     

基于RGV轨导柔性线环境离散型零件生产过程管理与实践

为满足航空中小型结构件快速交付的需要,以提升航空中小型结构件制造高精度、自动化和高效率为目标,通过对航空中小型结构件加工现状进行梳理分析,搭建柔性生产线自动排程与调度平台,实现柔性生产线工艺设计与准备过程管理,简化工艺准备流程,推进快换工装的应用并进行自动化程序管理;在柔性生产线加工运行过程中采用可视化管理方法,推动自动化环境下加工过程资源保障集中化管理。最终使该管理方法在某项目中进行成功实践,取得了良好的经济效益。     

拉深筋对板材变形特征和力学性能的影响研究

采用实验方法将金属板材拉过不同尺寸的拉深筋镶块，分析了拉深筋高度、圆角半径以及过筋次数对板材变形特征的影响规律，研究了过筋产生的预应变对板材后续力学性能的影响规律。结果表明：板材流过拉深筋后，流动方向上发生均匀的拉伸变形；过筋产生的预应变随着拉深筋高度增大而增大，随着圆角半径增大而减小，随着过筋次数增加而近似线性增大；预应变越大，材料后续屈服强度和抗拉强度越高，但后续延伸率越小，总延伸率随着预应变增大表现出先减小后增大的趋势。     

纳米零价铁材料对放射性核素的 去除及机理研究进展

随着人类社会的发展，放射性铀矿的开采和使用越来越多，环境面临着越来越严重的放射性污染问题。从生物和环境的角度来看，有效地清除环境中的放射性核素是核能利用过程中最重要的问题之一。纳米零价铁（nanoscale zero valent iron, nZVI）具有较大的比表面积和较高的活性位点，能显著提高放射性污染物的修复效率。本综述的目的是展示nZVI基材料对放射性核素的高效去除能力和环境修复作用。简介了常用的nZVI基材料（表面改性或多孔材料支撑的nZVI材料）及其对放射性核素的去除效果和相互作用机制（如吸附和氧化还原）。最后，对nZVI材料的应用和挑战给出个人见解。本综述有助于为高效去除放射性核素的nZVI材料的设计指明方向，为放射性核素的高效处理处置提供新材料。     

Stress intensity factor evaluations for a curved crack in orthotropic particulate composites using an interaction integral method

This paper develops a domain-independent interaction integral (DII-integral) for extracting mixed-mode stress intensity factors (SIFs) for orthotropic materials with complex interfaces. The DII-integral does not require material property gradients, and moreover its validity is not affected by material interfaces. Combined with the extended finite element method (XFEM), the DII-integral is employed to investigate a straight crack in an orthotropic functionally graded plate and a curved crack in orthotropic particulate composites.     

Microencapsulation of camellia oil to maintain thermal and oxidative stability with focus on protective mechanism

Camellia oil (CO) microcapsules were developed using chitosan–soybean protein isolate (CS-SPI) complexes as wall materials and transglutaminase (TGase) as the cross-linking agent. Results indicated that CO/SPI under the ratio of 1:2 exhibited the highest microencapsulation efficiency and yield, possessing the best encapsulation effect. Morphology observation showed that CO microcapsules were intact, compact and nearly spherical. The microencapsulated CO exhibited the improved thermal resistance and significantly lower peroxide values after 3 days storage, demonstrating that the produced microcapsule was a promising way to maintain the thermal and oxidative stability of camellia oil. It could be found evidence from FTIR, which indicated that covalent cross-linking and hydrogen bonding might be involved among wall materials, and physical interactions between the core and wall materials. Therefore, the produced CO microcapsules could be an effective way to protect camellia oil, which was helpful for improving the processing and storage qualities of camellia oil.     

基于ANSYS的脱溶机转子结构有限元分析及优化

大豆粕低温脱溶过程中,传统脱溶机转子的辐条式端板结构易出现疲劳断裂。通过对脱溶机转子辐条式端板的结构研究,建立力学模型,采用ANSYS软件对转子辐条式端板进行有限元分析,模拟辐条各截面上应力的变化,确定端板辐条应力集中位置。为该转子端板结构的改进方案提供理论依据。     

Synthesis of pH-responsive isolated soy protein/carboxymethyl chitosan microspheres for sustained pesticide release

In order to improve the utilization rate of avermectin (AVM), a complex was prepared by electrostatic self-assembly using isolated soy protein (ISP) and carboxymethyl chitosan (CMCS) for loading AVM to obtain ISP/CMCS@AVM microspheres. The encapsulation efficiency (EE), sustained release property, ultraviolet (UV) protective ability, and toxicity of the microspheres were evaluated, and the release kinetics of AVM from the microsphere at different pHs were investigated. The results demonstrated that the average particle size of ISP/CMCS@AVM was 283.95 nm, and the EE reached 88.42% for AVM after denaturation. After 70 h of exposure to UV light, the residual rate of AVM in ISP/CMCS@AVM was 78.12%, which was significantly higher than 35.18% in the AVM emulsion. Moreover, the formulation imparted pH sensitivity and sustained-release property to AVM and was consistent with the Korsmeyer–Peppas model, controlled by Fick diffusion. Finally, the insecticidal toxicity of ISP/CMCS@AVM did not differ significantly from that of unmodified AVM. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020 , 137, 48358.     

北方干鲜果害鼠绿色防控技术

文章介绍了北方干鲜果各种不同为害方式害鼠的相应的绿色防控技术,树根和树干害鼠中华鼢鼠、棕色田鼠宜采用银恒快速捕鼠器捕杀;果实害鼠岩松鼠、花鼠、北社鼠防治时等应采用坚果注射杀鼠剂精准灭鼠技术;果园地面害鼠大仓鼠、长尾仓鼠、黑线姬鼠等可采用TBS技术绿色防控;果实贮藏害鼠褐家鼠、黄胸鼠、小家鼠采用粘鼠板消灭。各类绿色灭鼠技术可为干鲜果害鼠的防控提供参考。