表面硬化滚道风电主轴轴承的疲劳寿命分析

建立一种针对表面硬化滚道三排圆柱滚子风电主轴轴承的疲劳寿命分析方法。首先,在卡迪尔坐标系中建立三排圆柱滚子风电主轴轴承的5自由度力学模型,分析计算在外部5个方向载荷联合作用下轴承的内部滚子载荷分布;然后,建立圆柱滚子与表面硬化滚道之间的弹塑性接触有限元模型,计算得到滚子接触载荷作用下滚道次表面的脉动应力分布;最后,根据Goodman方程将滚道脉动应力幅值转化为交变应力幅值,运用Basquin应力-寿命理论计算得到风电主轴轴承的疲劳寿命。结果表明,轴承的下风向外圈滚道承受来自风轮的推力载荷,其疲劳寿命最短;径向外圈滚道承受风轮的重力载荷,其疲劳寿命最长。轴承的疲劳寿命取决于下风向滚道。     

摩托车传动装置的使用与检修

目前，润滑链条的主要方式是加人润滑油。由于链条长期裸露在外，时间一长便会在其表面形成粉尘颗粒与润滑油的混合物，起不到良好的润滑效果。于是，有人将有润滑效果的石墨加人润滑油中拌匀，形成含石墨润滑油。使用时，先用抹布将链条与链轮擦净，然后将这种润滑油加入链条缝隙中。     

软胶胀管法

由于化工、发电设备热交换器的可靠性日益提高,胀管器的研制工作已趋于实际应用。过去采用滚子胀管法即利用滚子的滚压作用进行胀接,管子内表面往往容易加工硬化。在胀管过程中,管子受到连续往返的变形,由于受到双重作用力而使管壁减薄,有时甚至在管子内表面会产生微裂纹。此外,一般管子还可能会产生加工残余应力,而降低耐腐蚀性能。     

鳞片式锅炉链条起拱问题及预紧力分析

通过求解悬链线方程和建立上、下链条刚度间的关系,对鳞片式锅炉链条起拱的力学问题进行了探索,提出了前驱动锅炉链条设计及安全运行的一项指标——临界预紧力及其简单的判断和控制方法。最后,对前、后轴两种驱动方式进行了比较,工业锅炉链条炉排采用前轴驱动方式更为合理。     

提高内燃机时规链滚子耐冲击性能的研究

本文针对内燃机时规链滚子在多冲作用下易于发生早期断裂失效的问题，提出一种全新形式的滚子——卷制螺旋滚子，并理论分析了其结构尺寸与变形能之间的关系，并且通过实验证明了卷制螺旋滚子在耐冲击和抗压溃性能方面明显优于传统滚子，可大大提高内燃机时规链的使用寿命。     

某型柴油机中间传动齿轮的改装与设计

我们对某大型柴油机,中间齿轮滑动轴承过早磨损及中间齿轮枢轴支架紧固螺栓频繁断裂的现象进行了全面的分析,并重新进行了改装设计,将滑动轴承改为圆锥推力滚子轴承,将紧固螺栓的长度进行加长处理以达到降低刚度提高其疲劳强度的目的。     

喷丸强化处理对核电汽轮机低压叶片表面残余应力的影响

文章采用喷丸强化处理的方法对核电汽轮机低压叶片进行了表面处理,研究了喷丸强化处理对叶片表面残余应力的影响。实验结果表明：喷丸强化处理能够显著提高叶片表面的残余压应力并使残余压应力分布较均匀且不会在叶片表面形成微裂纹等有害缺陷。     

高压油泵驱动凸轮相位优化对正时链系的影响

采用仿真模拟与台架试验方法分析了高压油泵驱动凸轮相位优化对正时链系的影响。研究中根据凸轮轴负载确定了高压油泵驱动凸轮相位角度,并考虑了VVT的影响,仿真模拟分析了高压油泵凸轮相位优化对正时链系的链条张紧力、张紧器柱塞行程的影响;采用台架试验分析验证了高压油泵驱动凸轮相位优化对正时链系的影响。结果表明,高压油泵驱动凸轮相位优化可以减小正时链条张紧力与张紧器柱塞行程。研究结果对提高正时链系安全系数,发动机的可靠性具有重要意义。     

预负荷空心圆柱滚子轴承承载性能的有限元分析

利用有限元分析软件ANSYS对预负荷空心圆柱滚子(HCR)轴承的承载性能进行分析。主要计算预负荷空心圆柱滚子轴承的最底部滚子和次底部滚子的等效应力、接触应力和滚子内圈拉应力的分布情况,分析滚子空心度和过盈量对轴承应力和额定载荷的影响。通过分析和计算得到数据结果为预负荷空心圆柱滚子轴承的进一步优化提供参考依据。     

预负荷空心圆柱滚子轴承承载性能的有限元分析

利用有限元分析软件ANSYS对预负荷空心圆柱滚子（HCR）轴承的承载性能进行分析。主要计算预负荷空心圆柱滚子轴承的最底部滚子和次底部滚子的等效应力、接触应力和滚子内圈拉应力的分布情况，分析滚子空心度和过盈量对轴承应力和额定载荷的影响。通过分析和计算得到数据结果为预负荷空心圆柱滚子轴承的进一步优化提供参考依据。     

Dye sensitized photovoltaic cells: Attaching conjugated polymers to zwitterionic ruthenium dyes

The synthesis of a zwitterionic ruthenium dye that binds to anatase surfaces and has a built-in functionality that allows for the attachment of a conjugated polymer chain is presented. The system was found to adsorb on the surface of anatase anchored by the ruthenium dye. Two types of devices were prepared: standard photoelectrochemical (PEC) solar cells and polymer solar cells. The PEC solar cells employed a sandwich geometry between TiO₂ nanoporous photoanodes and Pt counter electrodes using LiI/I₂ in CH₃CN as an electrolyte. The polymer solar cells employed planar anatase electrodes and the complex was adsorbed onto the surface before evaporation of gold electrodes. Alternative devices were obtained by spincoating of the polymer solution onto PEDOT:PSS covered indium-doped tin oxide substrates. PEC solar cells gave the best results and the main finding was that the polymer chain served as a light harvesting antenna for the ruthenium dye.     

Influence of perfluorinated surfactants on the electrochemical behaviour of a lead electrode in sulfuric acid solution

The influence of various types of perfluorinated surfactants and their analogous hydrocarbon chain surfactants on the electrochemical behaviour of a lead electrode in sulfuric acid is studied by linear sweep voltammetry and cyclic voltammetry. The hydrogen evolution reaction is affected mainly by the type of the hydrophobic chain of the added surfactant (perfluorinated or hydrogenated). Nevertheless, these surfactants exert little expander acticn on the negative electrode, or even show an adverse effect on the discharge capacity of the lead electrode. A possible explanation is given in terms of the adsorption properties of different surfactants on the electrode surface during charge and discharge.     

溢流面滑模施工技术的应用

溢流面滑模施工技术在水利工程施工中成功应用的范例较多,本项目的主要特点是在项目所处地区材料及设备采购无法满足要求时,采用倒链、钢丝绳现有材料和设备,利用钢筋制作拉环,组合后代替电动卷扬机,较好的解决了滑模牵引滑动的动力问题。     

添加剂对钙基固硫剂固硫效果的影响

在大量的试验研究的基础上 ,探讨了各种添加剂对钙基固硫剂脱硫率的影响。并通过压汞试验 ,分析了高温煅烧之后的复合固硫剂的孔隙率及比表面积的变化。还在 3 5t/h链条炉上选用一种复合固硫剂进行了现场试验 ,得到较好的脱硫效果     

Modelling of turbulent wind flow using the embedded Markov chain method

Small wind turbines are usually installed to provide off-grid power and as such can be situated close to the load in a less-than-ideal wind resource. These wind regimes are often governed by low mean speeds and high wind turbulence. This can result in energy production less than that specified by the manufacturer's power curve. Wind turbulence is detrimental to the fatigue life of key components and overall turbine reliability and therefore must be considered in the design stage of small wind turbines. Consequently it is important to accurately simulate wind speed data at highly turbulent sites to quantify loading on turbine components. Here we simulate wind speed data using the Markov chain Monte Carlo process and incorporate long term effects using an embedded Markov chain. First, second and third order Markov chain predictions were found to be in good agreement with measured wind data acquired at 1 Hz. The embedded Markov chain was able to predict site turbulent intensity with a reasonable degree of accuracy. The site exhibited distinctive peaks in wind speed possibly caused by diurnal heating and cooling of the earth's surface. The embedded Markov chain method was able to simulate these peaks albeit with a time offset.     

Hydrogen crossover through perfluorosulfonic acid membranes with variable side chains and its influence in fuel cell lifetime

In this study, hydrogen crossover in long side chain Nafion 211 membrane and short side chain Aquivion membrane is studied under different conditions. It is found that both temperature and relative humidity significantly influence the hydrogen crossover in the polymer electrode membranes (PEMs). The difference in hydrogen crossover behavior between Nafion 211 membrane and Aquivion membrane is revealed. The influence of hydrogen crossover on the fuel cell lifetime is also investigated under open circuit voltage (OCV). It is proved hydrogen crossover in the PEM would lead to possible degradation of the PEM and the decrease of electro-chemical surface area in the catalyst of the single cell. Single cell assembled with Aquivion membrane shows slower OCV and ECSA decay compared to the Nafion 211 single cell. Our results suggest that the PEM fuel cell lifetime is closely related to the hydrogen crossover in the PEM. The current study also highlights the possibility of improving the fuel cell durability by rational design of the PEM morphology.     

Enhancement of the catalytic performance and coke resistance of alcohol-promoted Ni/MCM-41 catalysts for CH4/CO2 reforming

A series of Ni-based catalysts were prepared by the alcohol-promoted impregnation for CO₂ reforming of methane. In order to illuminate the effects of carbon chain numbers and hydroxyl group numbers on the catalytic performance and coke resistance of Ni-based catalysts, the samples were characterized by XRD, SEM, BET, H₂-TPR, FT-IR, XPS, TG, and TEM. The results show that the introduction of alcohol during impregnation promotes Ni²⁺ species into the channels of MCM-41, thereby strengthening the meatal-support interaction. Besides, the presence of alcohol decreases the particle size of Nickel and increases the surface adsorbed oxygen species over the surface of the support, thus promoting the coke resistance of the catalysts. As a consequence, NM-EG shows the highest catalytic performance, the highest stability, and the best coke resistance in all of the catalysts. This indicates that the main factor influencing the catalytic performance and coke resistance of the catalysts is the number of hydroxyl groups rather than the chain length of the introduced alcohol in the alcohol-promoted impregnation.     

雅鲁藏布江大峡谷地区特大地质灾害链发育现状及对策

雅鲁藏布江大峡谷地区位于我国西藏的南部,其构造运动活跃、强震多发、地表侵蚀作用强烈,由崩滑(冰崩)—碎屑流—泥石流—堰塞湖等灾害要素组成的特大地质灾害链频繁发生。这类超高位超远程的链式地质灾害影响范围广、流域性成灾风险很高,近70年以来已发生15次特大地质灾害链堵江事件,造成很大破坏。研究发现,其发生与活跃的新构造运动和地震活动、丰富的降水以及较强的冰川活动紧密相关,而沿河谷分布的高陡斜坡处的松散堆积体则为地质灾害链的发生提供了物源。本文就此依次分析了其形成所需的地形地貌、地质构造、地震活动和气象水文等条件。针对当前存在的问题,本文在最后提出了3条对策建议:①加强特大地质灾害链调查与识别能力;②加强特大地质灾害链监测预报预警与风险防范能力建设;③加强特大地质灾害链工程防灾减灾与应急处置能力建设。     

模拟PEM燃料电池环境下垫片材料的化学损伤研究

对暴露在模拟质子交换膜(PEM)燃料电池环境下的硅橡胶弹性体垫片材料的化学损伤情况进行探究。采用平衡溶胀法测定试样暴露在模拟PEM燃料电池环境下交联密度的变化情况。采用衰减全反射傅里叶变换红外光谱(ATR-FTIR)和X射线光电子能谱(XPS)对老化试样表面的化学成分进行研究。实验结果表明,试样在加速持久性实验(ADT)溶液中交联密度明显降低,在常规(RS)溶液中变化不明显。ATR-FTIR和XPS实验结果表明,在模拟燃料电池环境下,试样表面分子结构随暴露时间发生明显变化,试样表面化学损伤加剧。材料的化学损伤主要表现为硅橡胶主链的断裂和高分子交联区的水解。