Enhancement of the thermo-mechanical properties and efficacy of mixing technique in the preparation of graphene/PVC nanocomposites compared to carbon nanotubes/PVC

Thin films of poly vinyl chloride(PVC)/multiwalled carbon nanotubes(MWCNT) and PVC/graphene(GN) nanocomposites were prepared by mixing in the presence of different quantities of nanoparticles. Film casting was performed using tetrahydrofuran as a solvent. The as-prepared PVC/MWCNT and PVC/GN nanocomposites were characterized by scanning electron microscopy, Raman spectroscopy, X-ray diffraction,thermogravimetric analysis, differential scanning calorimetry, dynamic mechanical analysis, and diffused reflectance spectroscopy. Only the PVC/GN nanocomposite films were evaluated further for detailed mechanical analysis because of the poor dispersion of MWCNTs in PVC. The PVC/GN nanocomposite films were thermo-mechanically more stable than the PVC films. These nanocomposites have potential as a replacement material for PVC and PVC/MWCNT owing to their better dispersion and high stability.     

Research on Mechanical Properties of Chemical Fibers

Development and present situation of chemical fiber industry was briefly introduced. In this paper, a comparative study on mechanical properties of nylon, polyester, and polypropylene was done. The purpose of the study is to have a better understanding of the performance of the various fibers and their advantages and disadvantages, to explore their application environment.     

RecurDyn在机械原理教学中的应用研究

文章利用RecurDyn建立实体模型,进行机械动力学仿真分析,解决机械原理课程传统教学中的不足,激发了学生的兴趣,提高了教学效果.同时启发学生利用计算机辅助设计与分析解决实际工程中的问题,提高了学生的创新能力.     

油田用筒式永磁防蜡器的设计与机械强度校核

本文针对原油开采中防蜡难的问题,设计了一种筒式永磁防蜡器,该装置由壳体、导流锥、永磁体等部件组成,并对其进行了机械强度校核。     

产品图纸信息自动校对软件设计与开发

本文分析了对产品图纸信息进行校对的基本内容和流程，提出了根据图纸标题栏及明细栏信息正确构建产品结构树的基本思路和实现方法，通过编程实现了对产品图纸信息的自动校对，最终自动生成产品各类明细，可直接用于指导生产。     

PLA纤维的性能研究

本文研究了PLA纤维的表面形态、物理机械性能、吸水性、在碱性洗涤剂中的收缩性,以及酸、碱和有机溶剂对PLA纤维的强力损伤程度.结果表明:PLA纤维的强度与形态和PET纤维相近,吸水率比棉小但比PET纤维大,PLA纤维在碱性条件下缩水率和强力损失速率大,PLA纤维抵抗酸碱和有机溶剂的能力大小为:丙酮＞盐酸＞碳酸钠＞氢氧化钠.     

“教学做”一体化教学模式在高职高专院校“机械制造技术”中的应用

通过分析高职高专院校“机械制造技术”教学现状可知,实施“教学做”一体化教学模式是必然趋势.实践证明,实施“教学做”一体化教学模式,可操作性强,教学效果明显.     

刀型截齿截割煤岩的实验研究

采用煤岩截割综合实验系统对刀型割煤岩的截割过程进行了实验研究，得到了刀型齿截割过程有关参数的变化规律曲线，这对于提高刀型齿截割效率，对于有效地提高采掘机械的效益具有十分重要的作用。     

Microstructure evolution and mechanical properties of a hot-rolled Ti alloy

The microstructure evolution and mechanical properties of a hot-rolled Ti-5.1 Al-2.5 Cr-0.5 Fe-4.5 Mo-1.1 Sn-1.8 Zr-2.9 Zn titanium alloy sheet along the thickness direction were investigated.The results indicated that the hotrolled titanium alloy sheet presented different microstructures along the thickness direction owing to the uneven distribution of stress and temperature during the hot rolling.The grains in central region underwent a larger deformation,leading to relative complete grain fragmentation and the formation of fine grains.During the air cooling process followed by hot rolling,the fraction of a phase precipitated in the central region was lower than that in the regions near the surface of the sheet.During hot rolling process,more deformation energy transformed to thermal energy and lower cooling rate in the central region promoted the α→β phase transformation,resulting in the increasing of the dynamic recrystallization in the β phase.By contrast,the dynamic recrystallization for a phase decreased.Distinct {0001}_α and {001}_β textures were observed,and these textures were markedly strengthened with the increasing distance from the central region.Due to the softening induced by dynamic recrystallization and the strengthening by concentrated dislocations,the surface of the sheet exhibits highest yield strength and lowest elongation.     

Ameliorating mechanical properties and reducing anisotropy of as-extruded Mg-1.0Sn-0.5Ca alloy via Al addition

Effects of Al addition to a Mg–Sn–Ca ternary alloy on its microstructure and tensile properties after extrusion were studied via extrusion of Mg-1.0Sn-0.5Ca-xAl (x ​= ​0, 0.8, 2.4 ​wt%) sheets and analysis of the extruded materials. The results showed that Al addition not only refined the grain size (from 9.8 ​± ​0.7 ​μm to 8.3 ​± ​0.4 ​μm and 7.6 ​± ​0.5 ​μm) but also accelerated the generation of more second phase (from 0.98 to 1.72 and 4.32%). Except for the CaMgSn and Mg₂Ca in Mg-1.0Sn-0.5Ca alloy, new phase (Mg, Al)₂Ca appeared after Al addition. The addition of Al into Mg–Sn–Ca alloy induced the textural variation from an initially ED-split double-peaked texture to a weakened texture, i.e., divergent elliptical texture, due to the effect of particle stimulated nucleation. This eventually contributed to the improvement of mechanical anisotropy as well as the higher Hc value and n-value. For the strain hardening behavior when tension along the TD, the prolonged stage Ⅱ of Al-modified alloys was closely connected with the additional TD textural components, accelerating the activation of more basal slip. The decreased θⅢ0 in stage Ⅲ of Al-modified alloys is beneficial to the grain refinement and the emergence of more second phase.