关键词： 高校   学风建设   长效机制   探索与实践  

摘要： 学风是高校办学思想、办学质量的重要标志,也是学生学习精神、学习素养的重要体现,是大学精神和校园文化的重要组成部分.河南理工大学机械与动力工程学院历来重视学风建设,经长期探索实践,构建起以“明职责、强保障、促发展、蕴氛围、抓实效”为主体内容的学风建设长效机制,形成以“导、引、督、带、正、严、促、助、浓”为核心的学风建设九字策略,为优良学风创建和社会主义合格建设者与可靠接班人的培育夯筑了根基.

关键词： Metallic glasses   Martensitic transformation   Mechanical property   Molecular dynamics simulation  

摘要： The strength-plasticity trade-off of metallic glass (MG) has not still been effectively overcome. The introduction of shape memory alloy (SMA) is an effective way to improve the mechanical properties of MG. Here, the deformation behavior of amorphous/SMA Cu64Zr36/B-2-CuZr nanomultilayers (ASNMs) under tension loading is investigated by molecular dynamics (MD) simulation method. The results show that the peak stresses and flow stress of the ASNMs are greater than those of the monolithic MG regardless of SMA volume fraction. The martensitic transformation (MT) in the SMA phase limits the propagation of shear bands (SBs), avoids a runaway instability, and simultaneously induces plastic strain strengthening. The results also indicate that the plastic deformation mode of ASNMs changes from the interaction of multiple SBs dominated to finally brittle fracture caused by nano-pores aggregation with the increase of SMA volume fraction. This means that the plasticity and strength of ASNMs can be significantly improved by adjusting the volume fraction of SMA. The fruits stem from this paper may provide a valuable guidance and theory route for the design of high-performance MGs.

关键词： 醇类燃料   石化燃料   动力机械设计   防止火焰倒灌   节能减排  

摘要： 为了实现降低排放量、节约石油资源的动力机械设计目标,我们以醇类燃料为柴汽油的替代品,采用了部分燃气轮机、汽油类动力机械的设计理念。在该中,已经给出了该动力机械的基础理论和基本结构设计图,并且设计了防止火焰倒灌装置,进一步加强了动力机械的安全性。同时也为以后可加装的信息化、数字化系统预留了一定的空间,以方便该动力机械的后续升级与改造。

关键词： Dynamics (Mechanics)   Mechanical properties   Vocal cords  

摘要： This study focuses on the measured changes in dynamic behavior exhibited by eight synthetic vocal fold models with varying mechanical properties. Uniaxial tensile testing was conducted to determine changes in mechanical properties between materials made from silicone rubber and polydimethylsiloxane with varying mixing ratios. The results of the mechanical testing showed that the elastic modulus, E, varied from 20.6 to 437.4 kPa, the measured Poisson ratios, nu, spanned the range of 0.43-0.48, and the density, rho(VF), varied from 0.86 to 1.02 g/cm(3) across the eight samples. Vocal fold models were dynamically tested using a custom-built experimental setup that supplied a heated and humidified airflow to the synthetic vocal folds. The resulting sounds were recorded and analyzed to identify the change in fundamental frequency which spanned 66.8 to 342.6 Hz across the eight samples. In addition, a mathematical aeroelastic model of phonation was implemented to further investigate the relationship between the mechanical properties and phonation frequency. Finally, a proof-of-concept magnetic actuation method was demonstrated using magnetic elastomers to deform the synthetic vocal folds through the use of an electromagnet.

关键词： 动力电池   拆解机械   研究现状   发展趋势  

摘要： 文章采取文献调研与经验总结相结合的方法,对现有动力电池单体拆解机械的现状进行研究,从动力电池单体拆解的切割方式与电池自动化拆解机械两方面对文献知识进行梳理与归纳,以期实现对动力电池拆解机械未来发展方向的把握与展望。

关键词： 工程机械   柴油机   动力匹配  

摘要： 柴油机广泛装备于工程机械设备,其动力匹配主要由散热系统、进排气系统和燃油系统等部分组成。正确的匹配选型和合理的布置对柴油机乃至整个设备的高效运行都至关重要。当然,设备使用的过程中,及时规范的保养也非常重要。

关键词： Nuclear magnetic resonance spectroscopy  

摘要： Zr(iv) metal-organic frameworks (MOFs) UiO-68 and PCN-57, containing triphenylene dicarboxylate (TPDC) and tetramethyl-triphenylene dicarboxylate (TTDC) linkers, respectively, were doped with an H-shaped tetracarboxylate linker that contains a [2]rotaxane molecular shuttle. The new MOFs, UWDM-8 and UWDM-9, contain a [2]rotaxane crossbar spanning the tetrahedral cavities of the fcu topology while the octahedral cavities remain empty. C-13 solid-state NMR (SSNMR) spectra and solution H-1 NMR spectra verified that the [2]rotaxanes were included as designed. Variable-temperature (VT) cross polarization (CP) magic-angle spinning (MAS) C-13 SSNMR was used to explore the translational motion of the macrocyclic ring in both MOFs. The SSNMR results clearly show that the structure of the linker (***) affects the shuttling rate of the macrocyclic ring, although questions remain as to how rotation of the central phenylene unit of the strut might also affect the motion of the macrocycle.

关键词： Forced oscillator   Bifurcations   Magnetic force   Chaos  

摘要： In this paper, oscillations in the physical model consisting of two carts mounted on a guide are considered. The movement of the carts is restricted by the repelling permanent magnets. The interaction between carts is provided by a linear spring. The harmonic external loading is applied to one of the carts. According to the experimental studies, the period doubling cascade leading to the creation of a chaotic attractor occurs with an increase in the forcing frequency in the system. Chaotic attractor crises, quasi-periodic regimes, and finite periodic doubling cascade are revealed as well. To describe system's dynamics, the nonlinear mathematical model is developed. Based on the experimental data, the procedure of model validation is introduced. The numerical and qualitative analysis of the mathematical model allows one to identify bifurcation types, reveal unstable modes, and discover phenomena existing beyond the main period doubling cascade. (C) 2020 Elsevier Ltd. All rights reserved.

关键词： 急性呼吸窘迫综合征   俯卧位   机械通气   吸痰  

摘要： 目的观察俯卧位机械通气下不同吸痰深度对ARDS患者吸痰效果及血流动力学、血气指标的影响。方法选取2018年2月-2019年10月在我院接受俯卧位机械通气治疗的80例ARDS患者为研究对象,根据其吸痰方式的不同分为浅部吸痰组和深部吸痰组。比较两组吸痰效果、治疗前后血气指标、APACHEⅡ评分和Murray肺损伤评分、炎症细胞因子(IL-6、IL-10、hs-CRP)水平的差异。结果两组平均吸痰次数和吸痰间隔时间比较差异无统计学意义(P>0.05);两组治疗后MBP和CVP较治疗前增高,HR较治疗前降低,组间比较差异无统计学意义(P>0.05);浅部吸痰组治疗后SPO2高于深部吸痰组,PaCO2低于深部吸痰组;浅部吸痰组治疗后APACHEⅡ评分、Murray肺损伤评分、IL-6、IL-10、hs-CRP低于深部吸痰组(P<0.001)。结论俯卧位机械通气下不同吸痰深度对ARDS的吸痰效果均较好,而浅部吸痰创伤小,且对血气等指标的改善情况优于深部吸痰,可应用于临床。

关键词： Glucose   Hydrogenolysis   1   2-Propylene glycol   Heterogeneous catalysts   ZnO   Ru   C   Optimization of reaction conditions   Kinetic modelling   Thermodynamic analysis  

摘要： Transformations of glucose to 1,2-propylene glycol were studied over a mechanical mixture of ZnO and Ru/C catalysts in the presence of hydrogen. Different reaction conditions were evaluated by changing the reaction temperature and hydrogen pressure. In addition to the cascade mode of operation, also separate steps in the overall reaction network, such as hydrogenation of pyruvaldehyde and hydroxyacetone to 1,2-propylene glycol were investigated. Fructose as a starting material was also studied resulting in a propylene glycol yield of 37.5%. The optimal temperature for glucose transformation to propylene glycol was found to be 165 degrees C. The influence of temperature on the catalytic behavior was more prominent than the effect of hydrogen pressure. Thermodynamic analysis of glucose transformation to 1,2-propylene glycol was performed and a plausible kinetic model reflecting a complex reaction network was developed being able to describe the data in a reliable way.