浅谈如何做好高校班主任工作

如何对大学班级进行有效的引导和管理,逐渐成为教育界一个重要而迫切的课题。作为大学生日常教育和管理工作的主要执行者,当代大学班主任面临着一些特殊的问题和挑战,只有实实在在地做到以人为本、与时俱进、因材施教,以及不断提升管理水平与自身修养,才能收获事半功倍的功效。针对现下大学班主任工作中的一些特点,提出了若干可供参考的工作方法。     

Effect of friction reclaimed materials of waste brake-shoe on basic performance of mortar

Discarded train brake shoes mainly consist of steel-backed friction material. To be better reutilized, its essential features and its interaction in cement-based material need to be studied. Consequently, particle size analysis, SEM, IR and TGA were used to investigate two types of waste brake shoes, i e, mechanical grinding friction reclaimed material of waste brake-shoe (G-FRMWBS) and pyrolysis-friction reclaimed materials of waste brake-shoe (P-FRMWBS). The latter exhibited less organic content, larger range of particle size distribution and smaller medium particle diameter. Both types contained inorganic particles of spherical and irregular shapes, striped with steel fiber. Upon isometric substituting fine aggregates, G-FRMWBS lifted the strength of mortar effectively that was increased by 16.6% and 17.5% when the replacing rate was 5%; the value went up to 19.2% and 19.2% when the replacing rate was 10%. Moreover, inclusion of FRMWBS enhanced the chloride penetration resistance, and optimized the pore characteristic and ITZ (interfacial transition zone) as well.     

Model based laser-ultrasound determination of hardness gradients of gas-carburized steel

Gas carburizing is a common industrial process utilized for case hardening of low carbon steels. However, there is a lack of non-destructive evaluation systems for the measurement of hardness-depth profiles. We propose a novel measurement method for the determination of hardness-depth profiles of two-step gas carburized steel specimens. The method is based on the measurement of broadband laser excited Rayleigh waves. Rayleigh waves were generated by a pulsed Nd: YAG laser in the thermoelastic regime and measured with a heterodyne Mach-Zehnder interferometer in the near-field. From two measurements with different source to receiver distances the dispersion diagrams were calculated by means of the phase spectral analysis method. In order to simulate the observed dispersive behavior of the Rayleigh waves, first the two-step gas carburizing process was simulated using solutions of the diffusion equation. The resulting continuous hardness profile was then discretized into up to 100 layers. Thereafter the Rayleigh wave dispersion diagram was calculated from the discretized stack of layers using a delta-matrix formulation of the Thomson-Haskell transfer matrix method. In order to obtain best fitting hardness profiles, the simulated dispersion diagrams were fitted to measurements with a curve fitting algorithm. Comparison of the Rayleigh wave inversion method with destructively obtained Vickers hardness profiles shows good quantitative agreement.     

6063铝合金TIG焊接头的变形行为及等效模型

用有限元软件ABAQUS对平板对接6063铝合金TIG焊接头进行拉伸模拟,研究了HAZ宽度及板厚对焊接接头变形的影响规律,进而建立TIG焊接头有限元等效模型,并用带焊缝的6063铝合金薄壁方管的压缩模拟来验证等效模型的精确性.结果表明,与母材相比,力学性能不均匀的焊接接头中应力状态较为复杂,三向应力度在母材与HAZ交界处和焊缝与HAZ交界处存在突变,三向应力度最大值的位置从母材与HAZ交界处转变为焊缝与HAZ的交界处;力学性能不均匀的焊接接头中的三向应力度不仅取决于试样的厚度,还取决于接头的几何尺寸;铝合金TIG焊接头有限元等效模型宽度为20 mm;带焊缝铝合金薄壁方管的精细模型和等效模型的载荷-位移曲线吻合较好.     

基于SMW工法的城市深基坑开挖稳定性分析

SMW工法具有防渗性好、构造简单、施工速度快、工程造价低等优点,广泛应用于大型隧道工程、城市地下空间开发、高层建筑深基坑开挖支护工程等。以某城市深基坑工程的SMW工法围护结构为研究对象,在考虑水泥土与型钢的相互作用下,建立有限元数值模型,分析开挖过程中墙体位移和土体变形特点。结果表明:开挖深度对墙体侧向位移有显著影响;随着坡面荷载的增加,基坑内外水平方向和竖直方向沉降量均有所增大。     

二甲醚发动机低压共轨系统喷油器的仿真研究

低压共轨燃油喷射系统能实现二甲醚发动机的可控预混合燃烧,从而有效地提高二甲醚发动机整体性能和降低排放。本文基于发动机低压模拟系统控制机理,以实现可控预混合燃烧为目标,对该系统的核心部件—电控喷油器,建立共轨喷油器的数学模型,进行仿真研究,为今后的设计开发提供了必要的理论依据。     

高压共轨柴油机燃油状态系统的研究

通过对柴油机燃油状态系统的研究,并结合其对柴油机性能的影响进行系统地分析,确立了基于高压共轨柴油机燃油状态系统的控制策略,利用ASCET软件进行控制策略程序的编写和仿真,模拟结果表明,燃油状态系统可以满足柴油机的需求。     

石人沟露天转地下过渡Ⅰ区采场结构参数研究

针对石人沟铁矿露天转地下过渡期开采Ⅰ区地下采场结构参数问题展开了深入研究。通过建立有限元数值模型,对Ⅰ区9种不同方案的地下采场结构参数进行了数值模拟,得出了地下开采时矿房和边帮的应力、应变情况。在此基础上,从安全和经济角度出发,建立综合模糊评判模型,通过方案对比、综合评判,最终得出了合理的矿房结构参数,为确保矿山在地下采场和边帮稳定的前提下安全、经济的生产提供了理论依据。     

An FBG impact location system based on broadband light source and improved TDoA algorithm

When a structure material is damaged by impact events, the reliability and lifetime of the material will be severely affected. So impact location is considered as the prime approach for structural health and damage monitoring. In this study, a novel fiber Bragg grating (FBG) impact location system based on broadband light source is designed, aiming at the shortcoming of existing location systems based on FBG. An improved localization algorithm based on the time difference of arrival (TDoA) is proposed for impact location. According to this algorithm, the impact position can be accurately predicted without wave velocity. Impact planar location experiments are carried out for verification of the FBG impact location system and algorithm on a400 mm×400 mm×3 mm aluminum alloy plate. The resulted locating error shows high precision and good stability of the proposed system. This work has been supported by the National Natural Science Foundation of China (Nos.61503218, 61403233, 61573226 and 61473176), the Excellent Young and Middle-Aged Scientist Award Grant of Shandong Province of China (No.BS2013DX018), and the Natural Science Foundation of Shandong Province for Outstanding Young Talents (No.ZR2015JL021). E-mail:pangdan@163.com