摆动缸式油气悬挂系统动态特性参数敏感性分析

为研究摆动缸式油气悬挂自身参数变化对履带车辆中"负重轮-悬挂-簧载质量"系统的影响,在典型工况下,对该系统的动态响应特征展开参数敏感性分析.结合油气悬挂的结构特征建立机械-液压耦合的动力学模型,并应用试验台架测试结果评价该模型的有效性.选取摆动缸式油气悬挂的关键参数,分析其刚度与阻尼特性随关键参数的变化趋势,并在脉冲激励工况下分析上述参数变化对油气悬挂系统动态响应行为的影响.结果表明:油气悬挂刚度在悬挂变形量不大时受蓄能器内气体初始体积的影响较大,在悬挂压缩变形较大时受油气悬挂定位角的影响较大;簧载质量垂向加速度与负重轮动载荷在低频时受蓄能器初始气体体积影响最大,在高频时受阻尼阀孔截面积影响最大;悬挂动行程受关键参数的影响趋势与之相反.     

燃料电池车用超高速空压机永磁体结构强度研究

针对大功率燃料电池系统高速空压机转子永磁体离心拉应力破坏,采用解析法计算了额定转速时护套与永磁体间过盈量的大小及应力,采用有限元方法建立二维轴对称模型,计算了永磁体和护套内的应力分布,对比解析法与有限元方法的准确性.基于有限元法研究了温升和护套材料对永磁体应力的影响,结果表明,解析法和有限元法计算的各应力的相对误差不超过2.5％,而影响因素中转速和温升均会造成永磁体应力的显著提升,需要增大过盈量对转子永磁体保护.碳纤维护套相比合金护套可以至少降低42.1％的永磁体应力,且在高温工况下的效果更为显著.降低转速、增大装配过盈量以及改善转子冷却均能有效优化结构强度,而复合材料护套相比钢护套更适用于保护永磁体.     

自重荷载下非均匀支撑板式无砟轨道静态响应

针对高速铁路路基不均匀沉降诱发的板式无砟轨道几何形态和应力状态恶化问题,建立了高速铁路CRTSII型板式无砟轨道-路基三维有限元模型,模拟了64种路基不均匀沉降组合(波长5～40 m,波幅5～40 mm),提出了基于混凝土底座柔度的形态映射和应力水平定量表征方法.研究结果表明,轨道结构的形态映射特征主要由混凝土底座柔度决定,在沉降波长小于15 m、或者波长在15～20 m之间且沉降幅值大于15 mm时,轨道结构与路基因变形不协调而出现脱离.轨道结构变形量的增加会导致混凝土结构附加拉应力和路基接触应力的增大,且易接近或超过相应的强度允许值而产生损伤破坏.同时,增加混凝土底座的模量和厚度,对提高轨面几何平顺性的效果并不显著,反而会增大结构自身的拉应力和路基接触应力.     

假如我们能够活上一百万年

正大大延长人类寿命将会带来各种各样的机会,然而也有令人畏惧的风险……最近,科学家们发现了超过一亿年的细菌埋藏在海底,而且它们还活着。假如我们仅仅能够生存一百万年,将会发生怎样的变化呢?两个想法立刻涌上心头。首先,必须要限制学术界的任期。     

浅谈中小企业人力资源面临的问题及对策

人力资源管理是企业生存与发展的根本，尤其对于中小企业而言显得尤为重要，因为中小企业在我国的国民经济中占有十分重要的作用，对经济的发展起着决定性的作用。而人力资源作为企业管理的关键，也越来越受到企业管理者的重视。但是，由于目前我国的中小企业还没有形成完善、科学的人力资源管理系统，在人力资源规划认知以及技术人才方面还存在不少的问题，那么如何处理好企业目前面临的这种问题，加强人力资源管理，促进中小企业经济发展，是摆在我们面前的首要任务，本文就此展开探讨。     

基于分形理论的红层软岩填料缩尺料制备方法

采用分形理论研究了在室内采用球磨机制备与现场填料具有相同分形维的缩尺料的方法.基于对模拟现场重复破碎机制的考虑,选用球磨机作为破碎岩块制备缩尺料的设备.通过正交试验,研究了岩块初始粒径、球磨机转数、钢球数等参数对分形模型拟合优度、颗粒分形维的影响.在此基础上,通过中三轴制样试验进一步研究了试样制作过程对缩尺料二次破碎的影响.研究结果表明,对于红层软岩,采用破碎参数:球磨机转数100转,钢球数9个、岩块初始粒径20 mm,可以制备得到与现场原料相同分形维的中三轴试样缩尺料.     

Single-componentchemicallyamplifiedi-linemolecularglassphotoresistbased on calix[4]resorcinarenes

Calix[4]resorcinarene, prepared by the acid- catalyzed condensation of resorcinol and paraldehyde, was used as the core of the molecular glass compound. The hydroxyl groups of calix[4]resorcinarene were partly pro- tected by tert-butoxycarbonyl （t-BOC） and then esterified with 2-diazo-l-naphthoquinone-4-sulfonyl chloride （2,1,4- DNQ-C1）. Upon irradiation to 365 nm light, the 2,1,4-DNQ groups undergo photolysis to generate a small quantity of sulfonic acid other than indene carboxylic acid. The gen- erated sulfonic acid can further catalyze the deprotection of the t-BOC group. So, a new type of single-component chemically amplified i-line positive photoresist can be formed by the molecular glass compounds. The litho- graphic performance of the resist was evaluated with high resolution and photosensitivity with an i-line stepper.     

基于改进蚁群算法的多目标路径规划研究

传统蚁群算法因在复杂环境中容易产生死锁，导致部分蚂蚁失效，造成效率低下，迭代次数增多。为此，提出了一种利用环境信息引入环境因子来调整启发函数的方法从而降低死锁情况的发生，增加了有效蚂蚁的数量，从整体上提高了蚁群的搜索速度，扩大了搜索范围。同时，传统蚁群算法在路径规划中仅在理想地域内寻求最短路径，而多因素环境中最短路径往往并非最优解。为解决此问题通过在不同环境中对转移概率进行加权优化在追求路径最短的基础上提出多目标路径规划，丰富了蚁群算法的实用性和现实意义。最后经仿真实验对优化算法进行验证，证明了上述优化的可行性。     

Influence of alumina on mineralogy and environmental properties of zinc-copper smelting slags

An iron-silicate slag, from a zinc-copper smelting process, and mixtures of this slag with 5wt%, 10wt%, and 15wt% alumina addition were re-melted, semi-rapidly solidified, and characterized using scanning electron microscopy equipped with energy dispersive spectroscopy, and X-ray diffraction. The FactSageTM6.2 thermodynamic package was applied to compare the stable phases at equilibrium conditions with experimental characterization. A standard European leaching test was also carried out for all samples to investigate the changes in leaching behaviour because of the addition of alumina. Results show that the commonly reported phases for slags from copper and zinc production processes (olivine, pyroxene, and spinel) are the major constituents of the current samples. A correlation can be seen between mineralogical characteristics and leaching behaviours. The sample with 10wt% alumina addition, which contains high amounts of spinels and lower amounts of the other soluble phases, shows the lowest leachabilities for most of the elements.     

Mechanical properties of directionally solidified lead-antimony alloys

The Pb-17wt% Sb alloy was directionally solidified under two solidification conditions: with different temperature gradients (G=0.93–3.67 K/mm) at a constant growth rate (V=17.50 μm/s) and with different growth rates (V=8.3–497 μm/s) at a constant temperature gradient (G=3.67 K/mm) in a Bridgman furnace. Microstructure parameters, such as primary dendrite arm spacing (λ₁), secondary dendrite arm spacing (λ₂), and dendrite tip radius (R), were measured. The microhardness (Hv) and ultimate tensile strength (σ) of the directional solidification samples were also measured. The influences of solidification and microstructure parameters on Hv and σ were investigated. The results obtained in this work were compared with similar experimental researches in literatures. It is shown that the Hv and σ values increase with the increase of G and V, but decrease with the increase of λ₁, λ₂, and R.