基于中点移位和过程纹理的真实感地形生成

介绍了基于中点移位法快速生成地形模型高程场的方法。给出了基于高程场的过程纹理方法生成与地形模型相匹配的纹理。采用此法生成的地形可以用在仿真系统和游戏中。分析了真实感地形生成的相关研究工作，给出了完整的基于中点移位生成地形模型的方法及完整的基于高程场的过程纹理生成方法,总结了实验结果。     

机场沥青混凝土道面剩余寿命预测方法研究

道面结构的剩余寿命是机场中长期维护和改造计划编制的基础,对于机场的运营管理和优化决策具有重要意义.基于“道面族”概念的道面状况指数(PCI)预测模型是目前应用广泛且发展得较为成熟的经验回归预测模型.但是,PCI预测模型的传统建模方法是以长期、大量的数据积累为基础的,而我国民用机场的道面评价工作则刚刚开始专业化、制度化,相关数据比较匮乏.因此,通过对道面使用性能衰变规律的研究,利用现有数据资源,以上海虹桥国际机场为依托,通过回归分析建立了沥青混凝土跑道道面的国际平整度指数(IRI)与累计交通量的关系和IRI—PCI关系.以此为基础,构建了机场沥青混凝土跑道道面的PCI预测模型,应用该模型能够较为准确地预测沥青混凝土跑道道面剩余使用寿命.     

NiFeNb种子层对坡莫合金磁滞回线的影响

采用NiFeNb为种子层,制备(Ni82Fe18)1-xNbx(35 )/(Ni82Fe18)(150 )/Ta(30 )系列膜,并对其颗粒大小和磁滞回线等进行测量,探讨种子层中Nb含量x对坡莫合金磁滞回线的影响.结果表明:以NiFeNb作种子层能更好地改善坡莫合金的微结构.种子层厚度为20 ,Nb含量为24 4%时,磁滞回线有最小的回线面积、矫顽力和较小的不对称性.种子层影响坡莫合金磁滞回线的一个重要原因是脱附激活能等因素造成种子层具有不同的表面粗糙度,进而使坡莫合金具有不同的微结构.     

岩石分形节理光弹实验与数值模拟研究

从分形几何的观点出发，根据岩石结构面具有统计自相似特征，采用Mandelbrot-Weierstrass函数在聚碳酸脂板人为生成不同分维的分形曲线来模拟岩石节理不同的粗糙度，对该试样进行了一系列单压和压剪光弹实验。运用ANSYS系统，通过对模拟分形节理实验过程的数值模拟，研究了定量刻划节理粗糙性的分维对应力场分布变化的影响，并与光弹实验结果作了对比分析。研究表明，数值模拟结果与光弹实验结果有较好的一致。     

表面粗糙度的综合评定及混合谱模型

采用自回归谱分析结合改进周期图检验的方法，建立表面粗糙度的混合谱模型，以分离其中表现为离散谱的确定性谐波成分和表现为连续谱的随机性成分，并在此基础上提出综合评定表面粗糙度各种参数的方法，同时对AR模型的阶数与谐波成分识别给出较有效的经验判定方法．     

基于径向基函数神经网络的滚动轴承故障模式的识别

The impacts of different groove shapes, numbers, and angle of friction dish on transmitting torque, speed, push pressure in wet speeding clutch are discussed in this paper. Since the wet speeed governing clutch works within hydrodynamic lubrication mixture lubrication. boundary, lubrication and contact situation, the oils combining with a-hydrocarbon or polyester are getting widely used as lubricant.The power-law fluid model with Patir-Cheng average flow model, GT asperity contact model and oil film inertia are applied for average Reynolds equation setting, In order to investigate the relationship between average push pressure within hydrodynamic lubrication and mixture lubrication, average transmitting torque and output speed, the numeral calculation and analysis are presented. According to calculation, it is found that the groove shape, groove angle and groove numbers affect the average transfer torque and push pressure with the speed rate.     

超密齿面铣刀的铣削力波动特性及其影响

提出了一种超密齿面铣刀概念,并推导了x和y方向的铣削力计算模型,分析了超密齿刀具铣削力及其波动规律.结果显示:随刀具的转动铣削力呈锯齿状变化,x向铣削力波动呈现两个山峰状,在三齿同时参与切削时波动最小.y向铣削力波动随初始切入角的增大先增大后减小,对比发现超密齿刀具铣削力波动远小于疏齿刀具.提出用单位体积材料所需切向铣削力大小来评价超密齿刀具和疏齿刀具性能.通过超密齿面铣刀的铣削实验验证了铣削力计算模型,并发现铣削力波动是影响工件表面粗糙度的因素之一,同时也反映出超密齿刀具的加工优越性.     

高温合金轴向超声振动钻削减摩机理

针对高温合金钻削困难、钻削过程中摩擦力大等问题,采用超声振动技术加工.首先,分析了超声振动减摩机理,构建了平均摩擦力与振动参数之间的关系,并得出了平均摩擦力与振幅之间的变化趋势.建立轴向超声振动钻削系统,利用该系统对高温合金进行钻削加工.结果表明:振动振幅对孔壁表面质量的影响符合超声振动钻削的减摩特性.利用优化后的振幅超声振动钻削,与普通钻削相比,切屑形态更加规整,孔壁表面粗糙度值更小,表面质量更好.     

Dynamic release process of pollutants during suspended sediment transport in aquatic system

Pollutants release is highly consistent with suspended sediment concentration （SSC） in water column, especially during re-suspension and transport events. The present research focuses on pollutant dynamic release from re-suspended sediment, especially the vertical distribution relationship between them. The sediment erosion experiments on a series of uniform flow are conducted in a circulate flume. Reactive tracer （phosphorus） is used as the contaminant in fine-grained sediments to identify the release characteristic length and time. Experimental results show that the flow condition near-bed depends on the sediment surface roughness. The region with high turbulent intensities corresponds to a high concentration sediment layer. In addition, the SSC decreases with the distance, water depth, and particle grain size. The sediment in a smaller grain size takes much more time to reach equilibrium concentration. Total phosphorus （TP） concentration changes along the water depth as SSC in the initial re-suspension stage, appearing in two obvious concentration regimes： the upper low-concentration layer and the high-concentration near-bottom layer. This layered phenomenon remains for about 3 hours until SSC distri- bution tends to be uniform. Longitudinal desorption plays an important role in long-way transport to reduce the amount of suspended sediment in water column.     

Fabrication of robust superhydrophobic coatings using PTFE‐MWCNT nanocomposite: Supercritical fluid processing

Fabrication of polymer‐carbon composite nanostructure with good dispersion of each other is critical for the desired application due to the nanostructure flaws, agglomeration, and poor absorption between the 2 materials. Fabrication of superhydrophobic surface coating composites of polytetrafluoroethylene (PTFE) with multiwalled carbon nanotubes (MWCNTs) through supercritical fluid processing was explored in this study. Homogeneity of the composite was characterized by X‐ray diffraction and Raman spectroscopy studies, which reveal that the PTFE and MWCNT are uniform in the composite. Microstructural surface evaluation of field‐emission scanning electron microscope and high‐resolution transmission electron microscope studies display that the coating composite possesses roughness structures and fibrillation of the superhydrophobic surface coating. Superhydrophobic character was evaluated on fiber‐reinforced plastic (FRP) sheets, which showed that the prepared coating composite surface showed self‐cleaning properties with a high water contact angle of 162.7°. The surface wettability was studied by increasing different temperatures (30°C to 300°C) in PTFE‐MWCNT composite, which reveals that the FRP sheets were thermally stable up to 200°C and afterward; they transformed from superhydrophobic to hydrophilic state at 250°C. The superhydrophobic surfaces are thermally stable in extreme environmental conditions, and this technique may be used and extendable for large‐scale applications.