HIERARCHICAL CONTENT BASED IMAGE RETRIEVAL

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KZ1型转向架制动梁滑块磨耗套注塑成型工艺研究

以出口铁路货车KZ1型转向架制动梁滑块磨耗套产品为对象,从产品结构分析、模具设计、注塑机选型、工艺参数确定等方面开展工艺研究.模具型腔采用1模1腔、冷流道、2板模设计,模具四角以圆导柱为动定模导向机构.浇注系统采用盘形浇口进胶方式,以减少熔接痕数量;在分型面上开设排气槽,所有排气槽均与模具外侧联通,以实现良好排气;在产...     

现代双层有轨电车技术方案研究

双层有轨电车是路面轨道交通工具的重要型式之一.自有轨电车引入中国内地以来,近10年得到快速发展.但相比国外,双层有轨电车在中国内地的应用和适应性仍有较大发展和进步空间,有必要针对双层有轨电车开展进一步研究.介绍双层有轨电车国内外应用现状,详细叙述现代双层有轨电车技术平台、关键技术参数,分析适应性及应用前景.针对双层有轨...     

基于SEM的高校科技产业可持续发展驱动因素探讨

对高校科技产业可持续发展驱动因素进行了系统分析,指出政府支持和高校支持是高校科技产业可持续发展的外生因素,而吸收能力、知识传递能力和资源整合能力是高校科技产业可持续发展的内生因素,进而构建了涵盖内生和外生因素的概念模型,并基于结构方程模型方法和问卷调研数据对概念模型进行了验证.     

Preparation and Characterization of a Novel Hybrid Copolymer Hydrogel with Poly（ethylene glycol） Dimethacrylate, 2-Hydroxyethyl Methacrylate and Layered Double Hydroxides

This paper describes the fabrication, characterization and properties of a novel hybrid poly(ethylene glycol) (PEG) based hydrogel via in situ polymerization. The hybrid hydrogel was fabricated by free-radical redox polymerization using ammonium persulfate (APS) and N, N, N??, N??-tetramethylethylenediamine (TEMED) as initiators and N, N??-methylene bisacrylamide (BIS) as cross-linker at 60°C. To create a hybrid hydrogel, 0.2% (mass fraction) of MgAl layered double hydroxide (LDH) was added to the aqueous solution by ultrasonic dispersion. The physicochemical properties of hybrid hydrogel under vacuum freeze-drying processing were characterized by Fourier transform infrared (FTIR) spectroscopy, thermal gravimetric analysis (TGA) and scanning electron microscopy (SEM), while swelling kinetics and gel content were calculated. Swelling degree in distilled water varied from 94%?C125% with a gel mass fraction of 83%?C91%. SEM images showed that the micron pore size of hydrogel could be adjusted within the range of several micrometers by changing the cross-linker mass fraction from 2% to 10% (based on glycol). The results showed that the hybrid hydrogels exhibited excellent physicochemical behavior and might be a promising material for applications in tissue engineering and drug delivery.     

Effect of oil shale on Na+ solidification of red mud-fly ash cementitious material

Red mud-fly ash based cementitious material mixed with different contents of oil shale calcined at 700°C is investigated in this paper. The effect of active Si and Al content on the solidification of Na⁺ during the hydration process is determined by using X-ray diffraction (XRD), ²⁷Al and ²⁹Si magic-angle-spinning nuclear magnetic resonance (MAS-NMR), infrared (IR), scanning electronic microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). It is shown that the content of oil shale has a remarkable effect on the solidified content of Na⁺. The hydration process generates a highly reactive intermediate gel phase formed by co-polymerisation of individual alumina and silicate species. This kind of gel is primarily considered as 3D framework of SiO₄ and AlO₄ tetrahedra interlinked by the shared oxygen atoms randomly. The negative charges and four-coordinated Al inside the network are mainly charge-balanced by Na⁺. The solidifying mechanism of Na⁺ is greatly attributed to the forming of this kind of gel.     

橡胶沥青应用技术探讨

橡胶沥青作为新型路面材料,可以改善道路使用功能,延长使用寿命,减轻废轮胎带来的环境压力,符合我国当前建设节约型社会和发展循环经济的政策。本文结合近年来橡胶沥青的生产和施工经验,从橡胶沥青的技术性能、试验检测和施工技术等方面进行了探讨和总结,为橡胶沥青的应用和推广提供技术支撑。     

Pre-concentration and determination of amitriptyline residues in waste water by ionic liquid based immersed droplet microextraction and HPLC

This paper describes a new approach for the determination of amitriptyline in wastewater by ionic liquid based immersed droplet microextraction (IL-IDME) prior to highperformance liquid chromatography ...     

对联锁报告区段状态和车载报告列车位置信息不一致问题的分析与研究

CTCS-3级列控系统的列车走行累计误差如果过大,有可能造成联锁设备向RBC报告区段占用状态与车载设备向RBC报告列车位置之间存在信息不一致问题,导致列车运行效率降低,影响行车安全.本文针对该问题进行了数学建模,通过对模型的分析研究,说明了问题发生的原因,并提出了降低问题发生概率的方法.     

CBTC系统中移动闭塞与后备模式追踪间隔研究

为了探讨基于通信的列车控制(CBTC)系统后备模式下追踪间隔的特性及与正常情况下追踪间隔的差异,在研究CBTC系统基本工作原理、相关移动闭塞和后备模式技术的基础上,建立了CBTC后备模式下的追踪间隔仿真模型,并对CBTC系统在移动闭塞和后备模式下的追踪间隔进行了仿真计算.结果表明:CBTC移动闭塞模式和后备模式都能满足系统要求,实现较小的追踪间隔时间;移动闭塞模式优于后备准移动闭塞模式,能够实现相对更小的追踪间隔时间(<90 s).