Delay Estimates of Mixed Traffic Flow at Signalized Intersections in China

Two characteristics of Chinese mixed traffic invalidate the conventional queuing delay estimates for western countries.First,the driving characteristics of Chinese drivers lead to different delays even though the other conditions are the same.Second,urban traffic flow in China is often hindered by pedestrians at intersections,such that imported intelligent traffic control systems do not work appropriately.Typical delay estimates for Chinese conditions were obtained from data for over 500 vehicle queues i...     

浅谈变电运行危险点预控

在电力系统运行中,变电运行是电网运行管理,倒闸操作和事故处理机构。每个值班员是保证电网安全运行、稳定运行和经济运行的直接执行者。在电网运行中,任何不规范的行为,都可能影响电网安全,稳定运行,甚至造成重大事故。我们相信,除人力不可抗拒的自然灾害外,通过我们的努力,事故都应当可以预防,隐患都应当可以控制。     

六氟乙酰丙酮离子液体的合成及摩擦学性能研究

合成了三种含有六氟乙酰丙酮阴离子和不同烷基链长咪唑阳离子的室温离子液体([C_nmim][hfac];n=4,6,8)润滑剂,以1-丁基-3-甲基咪唑双三氟甲烷磺酰基亚胺盐(L-F104)为参照样,研究了它们作为不同金属摩擦副润滑剂的摩擦学性能和理化性质,并探索了其结构中阳离子烷基链长的影响规律. 结果表明:[C_nmim][hfac]离子液体对金属基底材料腐蚀较轻,常温下作为钢/铜和钢/铝摩擦副的润滑剂均具有良好的润滑性能,并且随着其结构中阳离子烷基链的增长,热稳定性和黏度呈递增趋势,减摩抗磨作用也更加优异.      

Three-and two-dimensional calculations for the interface anisotropy dependence of magnetic properties of exchange-spring Nd2Fe(14)B/α-Fe multilayers with out-of-plane easy axes

Hysteresis loops,energy products and magnetic moment distributions of perpendicularly oriented Nd2Fe(14)B/α-Fe exchange-spring multilayers are studied systematically based on both three-dimensional(3D)and one-dimensional(1D)micromagnetic methods,focused on the influence of the interface anisotropy.The calculated results are carefully compared with each other.The interface anisotropy effect is very palpable on the nucleation,pinning and coercive fields when the soft layer is very thin.However,as the soft layer thickness increases,the pinning and coercive fields are almost unchanged with the increment of interface anisotropy though the nucleation field still monotonically rises.Negative interface anisotropy decreases the maximum energy products and increases slightly the angles between the magnetization and applied field.The magnetic moment distributions in the thickness direction at various applied fields demonstrate a progress of three-step magnetic reversal,i.e.,nucleation,evolution and irreversible motion of the domain wall.The above results calculated by two models are in good agreement with each other.Moreover,the in-plane magnetic moment orientations based on two models are different.The 3D calculation shows a progress of generation and disappearance of vortex state,however,the magnetization orientations within the film plane calculated by the 1D model are coherent.Simulation results suggest that negative interface anisotropy is necessarily avoided experimentally.     

CaYO(BO3)3晶体坩埚下降法生长

本文首次报道了Ca4YO(BO3)3(YCOB)晶体的坩埚下降法生长.在1600～1650℃炉温下,固液界面处的纵向温度梯度为40～60℃/cm,以0.2～0.6mm/h的生长速率,在近封闭的Pt坩埚中生长出了直径达25mm、长度超过50mm的完整透明YCOB晶体.介绍了生长工艺和原料制备,观察发现晶体中的主要宏观缺陷是包裹体.分析了包裹体生成的原因.     

微波等离子体发射光谱法测定乳及乳制品中的11种元素

本文采用微波灰化技术处理乳及乳制品试样,利用微波等离子体发射光谱法(MP-OES)测定乳及乳制品中K、Ca、Na、Mg、Fe、Zn、Mn、Cu、Ba、Cr、P 11种矿物质元素.实验对样品前处理条件和仪器工作参数进行了优化.结果表明,K、Ca、Na、Mg、Fe、Zn元素的线性范围为0.2～3.0μg/mL,Mn、Cu、...     

碱污染下红黏土强度指标变化的微观角度分析

为了研究碱性环境条件下桂林红黏土强度指标变化机制,对不同质量分数NaOH溶液污染下的红黏土开展直剪试验、物化分析试验、颗粒分析试验以及比表面积试验,进而探究地基土体宏观力学指标与微观结构之间的关系.研究结果表明:随着NaOH质量分数的增加,黏聚力逐渐增大,内摩擦角逐渐减小.随着孔隙溶液中Na+质量分数的增加,微小土颗粒...     

面向2035年中国科技人才集聚机制研究

面向2035年,中国科技人才集聚在推动中国科技创新、促进产业升级、提高经济竞争力等方面的作用日益突出,探索中国科技人才集聚机制对增强中国科技实力意义重大.通过对中国科技人才集聚现状、科技人才集聚效应、科技人才集聚的影响因素及科技人才集聚模式梳理的基础上,构建面向2035年中国科技人才集聚机制的框架.提出集聚全球科技人才...     

基于高光谱的水体BOD含量模拟估算

高光谱技术由于满足连续性与光谱可分性的要求,具有能够区别同一种地物不同类别的能力,且光谱数据获取速度快,操作简易,在监测水体分布状况、水体指标上具有突出成就.生化需氧量BOD是评价水污染的重要指标,现行常规的测量方法为五日培养法,这种方法消耗试剂、操作复杂、受干扰因素多、测定时间长、不能及时反映水质变化、无法及时有效地...     

从复杂XML文档中抽取目标关系片段的方法

针对以往关系信息挖掘中存在的复杂XML文档相似度计算精度不高的问题,提出通过发现包含目标关系信息的最小公共祖先节点SCATR,以SCATR节点为根对复杂文档进行片段划分,并按片段的相似度进行聚类,目的在于改善已有模型对复杂XML文档的识别效果.实验结果表明,通过抽取包含目标关系的文档片段,去除文档片段中无关分枝,能够有效地帮助已有模型从复杂XML文档中识别和抽取出目标关系信息.