自行火炮扭力轴强化疲劳寿命计算及分析

开展自行火炮强化试验研究,关键问题是如何计算强化路面下自行火炮扭力轴疲劳寿命.首先,基于虚拟样机技术,建立了某型自行火炮的虚拟样机,结合强化路面数字化模型,开展自行火炮行驶强化试验仿真,获得自行火炮悬挂装置关键件扭力轴的载荷时间历程.然后,利用有限元分析软件MSC.Nastran与疲劳分析软件MSC.Fatigue计算其疲劳寿命.最后,针对自行火炮在部分强化路面上行驶时,随着车速的提高,出现了扭力轴疲劳寿命不降反升的现象,利用振动学的相关理论,从路面、车速对载荷的影响规律入手,对这种现象的原因进行了分析,为自行火炮实车强化行驶试验方案的制订提供了数据参考.     

板料成形模拟后处理中的截面物理量的显示技术*

在自行开发的板料成形有限元后置处理系统FASTAMP_POST中,采用了动态获取截面物理量的算法,实现了截面物理量实时显示功能。该功能真实反映了网格物理量的大小及其变化趋势,具有原理简单、易实现、执行速度快的优点。     

Effect of supports on the redox performance of pyrite cinder in chemical looping combustion

Chemical looping combustion (CLC) is a clean and efficient flame-free combustion technology,which combust the fuels by lattice oxygen from a solid oxygen carrier with inherent CO2 capture.The develop-ment of oxygen carriers with low cost and high redox performance is crucial to the whole efficiency of CLC process.As the solid by-product from the sulfuric acid production,pyrite cinder presented excellent redox performance as an oxygen carrier in CLC process.The main components in pyrite cinder are Fe2O3,CaSO4,Al2O3 and SiO2 in which Fe2O3 is the active component to provide lattice oxygen.In order to sys-tematic investigate the functions of supports (CaSO4,Al2O3 and SiO2) in pyrite cinder,three oxygen car-riers (Fe2O3-CaSO4,Fe2O3-Al2O3 and Fe2O3-SiO2) were prepared and evaluated in this study.The results showed that Fe2O3-CaSO4 displayed high redox activity and cycling stability in the multiple redox cycles.However,both Fe2O3-Al2O3 and Fe2O3-SiO2 experienced serious deactivation during redox reactions.It indicated that the inert Fe-Si solid solution (Fe2SiO4) was formed in the spent Fe2O3-SiO2 sample,which decreased the oxygen carrying capacity of this sample.The XPS results showed that the oxygen species on the surface of Fe2O3-CaSO4 could be fully recovered after the 20 redox cycles.It can be concluded that CaSO4 is the key to the high redox activity and cycling stability of pyrite cinder.     

高铝高炉渣系的熔化特性

 为了掌握高Al₂O₃条件下(w(Al₂O₃)为15%以上)高炉渣系的熔化特性,利用差式扫描量热仪分析了不同w(MgO)/w(Al₂O₃)、碱度(R)以及w(Al₂O₃)对高铝高炉渣的熔化温度及熔化热的影响。试验结果表明,炉渣熔化开始温度为1 248～1 291 ℃、熔化结束温度为1 432～1 485 ℃、熔化热为137～211 J/g;当w(Al₂O₃)=15%、高w(MgO)/w(Al₂O₃)时,发生了共晶逆反应,导致高炉炉渣熔化开始温度逐渐降低,但由于高炉炉渣的液相线温度基本未变,所以炉渣熔化结束温度基本未发生改变;w(Al₂O₃)为20%时,随着w(MgO)/w(Al₂O₃)的增加,炉渣中易生成熔点较高的镁铝尖晶石,导致高炉炉渣熔化开始温度逐渐增大,与此同时,炉渣液相线温度逐渐降低,导致炉渣熔化结束温度逐渐降低;随着碱度R的增加,高炉炉渣中生成了具有高熔点的化合物、炉渣的液相线温度升高,使得高炉炉渣的熔化开始温度逐渐增加、炉渣熔化结束温度逐渐升高;随着w(Al₂O₃)的增加,发生了共晶逆反应,故炉渣的熔化开始温度逐渐降低,而随着w(Al₂O₃)的增加,炉渣中键能较大的Al—O键增多,需要在更高温度下才能实现炉渣的最终熔化,即熔化结束温度逐渐增加;随着w(MgO)/w(Al₂O₃)、R以及w(Al₂O₃)的增加,炉渣熔化热逐渐增多。分析认为,随着R的增加,炉渣中有高熔点化合物的生成,熔化热增加;随着炉渣中w(Al₂O₃)的增加,炉渣中Al—O键增多,解聚破坏熔渣结构消耗的热量增多;而随着w(MgO)/w(Al₂O₃)增加,高熔点化合物的生成或熔化开始温度降低,造成熔化热增加。     

6m大容积焦炉烘炉实践与体会

介绍了 6 m大容积焦炉由冷态到转入正常加热温度的烘炉操作过程中 ,按照一定的升温曲线 ,通过对焦炉热工和炉体膨胀的科学管理 ,确保新建焦炉顺利由冷态过渡到生产状态。     

基于蚁群聚集信息素的半监督文本分类算法

半监督文本分类中已标记数据与未标记数据分布不一致,可能导致分类器性能较低。为此,提出一种利用蚁群聚集信息素浓度的半监督文本分类算法。将聚集信息素与传统的文本相似度计算相融合,利用Top-k策略选取出未标记蚂蚁可能归属的种群,依据判断规则判定未标记蚂蚁的置信度,采用随机选择策略,把置信度高的未标记蚂蚁加入到对其最有吸引力的训练种群中。在标准数据集上与朴素贝叶斯算法和EM算法进行对比实验,结果表明,该算法在精确率、召回率以及F1度量方面都取得了更好的效果。     

Flakes of natural carbyne in a diamond mine

Flakes of natural carbyne were found in Liao-Ning diamond mine, China, and examined by HRTEM, XRD and EDX. Lattice fringes and clear SAD patterns were obtained. The interlayer spacings obtained with SAD were in good agreement with those determined on the powders found in Ries crater meteorite by X-ray diffraction. However, they are different in color and shape, the one found in China being black and flaky, but the one in Ries crater meteorite being silver-white and particulate. It was assumed that carbyne might be stabilized by the intercalation of either Si or Fe in nature.     

基于改进的SKPCA三维模型检索方法

本文提出了改进的SKPCA降维方法。在特征向量稀疏化表达的基础上,实现了一阶降维、二阶降维与非线性降维。在增强特征向量表达能力的同时最大限度去除了冗余信息。实验证明利用改进的SKPCA降维方法获得的特征向量,检索效果优于SPCA方法。     

光纤光栅传感器中磁场测量稳定性研究

为了减小光纤光栅磁场传感器中线性双折射和入射起偏角对系统稳定性的影响,提高测量系统的准确性,提出一种减小线性双折射和起偏角大小对系统输出影响的设计方案。研究了基于法拉第效应的光纤光栅磁场传感器系统,得出系统输出电压与磁场的关系式,并通过降低线性双折射和确定入射起偏角改善了系统的输出特性。仿真表明:该方法可以有效抑制测量过程中线性双折射造成的非线性关系,从而提高磁场测量的稳定性。