Effect of nanostructured grains in co-sputtered Ni-GDC thin-film anode on methane conversion kinetics for low temperature solid oxide fuel cells operating on nearly dry methane

Direct-methane solid oxide fuel cells (DMSOFCs) have recently attracted substantial attention due to their simplified system, reduced cost, and the direct availability of methane fuel obtained from natural gas. Among oxygen-ion conductive materials, doped-ceria such as gadolinium-doped ceria (GDC) or samarium-doped ceria can be incorporated into Ni-based anodes to reinforce their coking resistance, enlarge their electrochemical reaction area, and improve the kinetics of the internal reforming/electrochemical oxidation of methane. To reduce the range of operating temperatures of DMSOFCs while maintaining their performance, the thin film deposition technique of magnetron sputtering was adopted in this work. An Ni-GDC thin-film anode and a Pt thin-film cathode were deposited on scandia-stabilized zirconia (ScSZ) electrolyte supports. This fuel cell was tested with directly supplied methane fuel (3% H₂O) at 500 °C. The results demonstrated the effects of the GDC volume fraction in the anode—which was controlled by co-sputtering power—on open circuit voltage and electrochemical performance. The co-sputtered Ni-GDC anode was able to survive through 36-h operation, although there was some performance degradation. Field-emission scanning electron microscopy results revealed no formation of filamentous carbon on the Ni catalysts, despite the fact that both X-ray photoelectron spectroscopy and Raman spectroscopy analyses detected carbon coking. The relatively high performance and resistance to carbon coking of co-sputtered thin-film anode were attributed to its intrinsic small grain size.     

车用有机朗肯循环系统中计量泵的性能研究

在模拟车用有机朗肯循环(organic Rankine cycle,ORC)系统的工作环境下,设计并搭建以R123作为工质的液压隔膜计量泵性能测试平台。在额定转速(2900 r/min)下,通过调节液压隔膜计量泵的冲程(25%、50%、75%、100%)和出口压力,得到变工况下液压隔膜计量泵的特性曲线,并分析液压隔膜计量泵的关键参数对车用ORC系统性能的影响情况。结果表明:液压隔膜计量泵的流量受冲程影响,与出口压力基本无关。其输入功率和实际运行效率均随着冲程的增加而升高,最高分别可达523.91 W、88.27%。应用该液压隔膜计量泵的模拟车用ORC系统吸热量变化范围较广,系统热效率最高可达12.81%。液压隔膜计量泵可应用于车用ORC系统,通过调节液压隔膜计量泵的冲程和出口压力,可实现提高车用ORC系统热效率、增加系统净输出功率的目的。     

纵轴式掘进机截割头载荷影响因素的仿真分析

针对现有掘进机截割头载荷特性研究方法采用单一影响因素不能全面反映截割头载荷及其波动变化规律的问题,通过分析截割头瞬时载荷,确定了纵轴式掘进机在水平截割工况下截割头载荷的主要影响因素有截割岩石特性、截割头掏槽深度、截割头吃刀深度、截割头转速和截割臂摆速。针对某纵轴式掘进机水平截割工况,采用Matlab对影响截割头载荷的多种因素进行仿真分析,得到了各向载荷及其波动随各因素的变化规律:截割头载荷随着岩壁普氏系数的增大而增加,其中横向阻力增加尤为明显,横向阻力波动程度高于其他方向载荷,且随着岩壁普氏系数的增大呈减小趋势;随着截割头掏槽深度的增加,截割头各向载荷近似呈线性增加,其中升力增加幅度最大,各向载荷波动则随着截割头掏槽深度的增大而减小;随着吃刀深度的增加,截割头载荷总体呈增大趋势,载荷波动程度则随之减小;在截割头转速一定的情况下,截割头载荷均随着截割臂摆速的增加而增大,在同一摆速下,截割头载荷随着截割头转速的减小而增大,横向阻力波动明显高于升力和推进阻力波动,横向阻力和推进阻力波动按截割头载荷规律变化,升力波动则与之相反。截割头载荷波动变化规律与截割头载荷变化规律不尽一致,有时甚至相互冲突。因此,掘进机作业过程中应合理选择截割头掏槽深度、吃刀深度等操作参数和截割头转速、截割臂摆速等运动参数,使各参数相互匹配,以减小掘进机振动,延长使用寿命。     

The structural variability of quarters and residential areas in the historical texture of the city of Yazd based on Islamic rules and jurisprudence: a case study of Golchinan quarter

According to many researchers and scholars, religious beliefs can be considered as the most influential factor in forming Muslim urban spaces and their architectural elements. In fact, historical cities reflect the culture and beliefs of their residences. Among all historical places in Iranian cities, the historical texture of the city of Yazd, especially the quarters since the age of Qajar dynasty, are well preserved. The present study aims at identifying the Islamic principles and values influencing the formation of architectural spaces and the extent of their applications in one of the historical quarters known as Golchinan. The results of the conformation of the theoretical findings with the data acquired from field studies revealed that almost 90% of the urban and architectural spaces (e.g. residential areas, mosques, bazaars, and pathways) in Yazd are directly influenced by Islamic principles. In other words, there is a strong conformity between the accepted Islamic values of the society and what actually was applied to urban constructions during Qajar dynasty.     

γ辐照加工用新型工作模体设计研究

本文研究设计了一种用于获取γ辐照装置辐射场和货物剂量场真实分布的新型工作模体。基于真实γ辐照装置参数构建了有效可用的模拟辐射场，提出了新型工作模体的结构和填料设计方法。采用蒙特卡罗方法和随机填充方法（RCS）模拟计算剂量计套管材料与壁厚、填料小球尺寸、空心填料小球尺寸与壁厚、小球填充方式等影响模体剂量学性能的主要因素的分布规律。在满足计算置信度的前提下，参数优化取值范围为：套管采用壁厚为3~5 mm的铝管，对辐射场干扰不超过4.372 23%；填料选择外径为1~4 cm、壁厚为1.1~11.5 mm、材料等效性好、货物密度模拟范围为0.1~0.5 g/cm³的聚丙烯小球，对辐射场干扰不超过9.998 44%；均匀填充和随机填充模式对辐射场干扰基本持平，且均不超过10%。结果表明，当前设计可行有效，投入低、兼顾参数多且量程更宽，适合推广应用。     

Title加TextRank抽取关键句的情感分类研究

考虑到不同句子对判断文档情感倾向的重要程度不同，因而区分文档的关键句和细节句将有助于提高情感分类的性能。同时，考虑到Title和上下文信息，提出了一种基于Title和加权TextRank抽取关键句的情感分析方法SKTT，实现了高效的情感分析。根据文档Title的情感权重计算Title贡献度，考虑到标点和语义规则对情感倾向的影响；根据加权TextRank算法思想，在文档正文中构建了一个情感句有向图来提取关键句；计算所有关键句的情感倾向进行情感分类。在4个领域上进行实验，实验结果表明，该SKTT方法性能明显优于Baseline，具有高效性。     

基于改进蚁群算法的三维路径规划

针对移动机器人在海水环境中的三维路径规划问题容易陷入局部最优和收敛慢等瑕疵，根据三维环境全局信息来改进蚁群算法以提高实时性和收敛速度。改进蚁群算法的启发函数，采用局部信息和全局信息结合动态地改进信息素更新方式，以及根据三维空间中路径的平坦程度和光滑度二阶微分分别增加了一阶微分和二阶微分来再次修改信息素更新规则。仿真对比实验结果显示改进后的蚁群算法克服了收敛速度慢、容易陷入局部最优的缺点。     

Discovery of path-attribute dependency in manufacturing environments: A process mining approach

The more knowledge industrial practitioners detain of their production processes, the more they are capable of performing process improvements. Nonetheless, there may exist process characteristics and dependencies that are not easily extractable from business models, such as routing dependent attributes. This paper introduces an algorithm-driven framework to establish whether process path decisions influence the attributes in non-direct sequences, e.g., deploying machine A instead of machine B affects the % of rejected parts on the process, 4 stages down the line. This problem is shown to bears similarities with sequential pattern mining problems. The basis of the solution framework relies on process mining and data mining techniques. The approach proposed is applied on a real industrial log, unveiling deficiencies in the system and providing further improvement recommendations.     

运营高速公路 40m 预制箱梁拆换施工技术研究

对于运营高速公路40m箱梁拆换施工，梁体的切割、吊装、运输、架设等受作业空间和环境的限制，增加了施工困难和风险，新旧箱梁在高速公路上的长距离运输为施工增加了成本和安全风险，同时也决定了箱梁拆换的总体进度。韩河大桥梁体拆换工程按期顺利实施完成，有效化解了以上问题，取得了良好的经济、社会效益。     

基于Unity 3D的岩心钻机模拟操作系统设计与实现

自2008年起,我国地勘行业投资规模迅速增长,随后快速回落,近年来市场规模趋于稳定,预计2020年我国的岩心钻机相关市场规模约为100亿元左右,从业人员也将超过5万人。为了使我国岩心钻机操作人员能够掌握在“高精尖”设备转型下的自动化全液压岩心钻机的操作技能,本研究利用虚拟现实技术,还原岩心钻机的实际现场工作状态；采用SolidWorks,3ds Max,Cinema 4D等软件对钻机进行三维建模、坐标更改和纹理着色；以C#语言为脚本,研究关键帧动画设定、摄像机视角控制、刚体碰撞模块、射线检测等技术,提出基于Unity 3D的岩心钻机模拟操作系统设计方案并最终实现。该模拟操作系统具有多视角展示、钻进控制、参数显示和语音指导等功能,呈现了能够身临其境的钻机操作体验。