Discrimination for ablative control mechanism in solid-propellant rocket nozzle

The ablation in solid-propellant rocket nozzle is a coupling process resulted by chemistry, heat and mass transfer. Based on the heat and mass transfer theory, the aero-thermo-dynamic, and thermo-chemical kinetics, the thermal-chemical ablation model is established. Simulations are completed on the heat flow field and chemical ablation in the nozzle with different concentrations, frequency factors and activation energy of H2. The calculation results show that the concentration and the activation energy of H...     

视线追踪系统中视线估计方法研究

文中提出一种基于瞳孔—角膜反射(PCCR)的视线估计方法(GEMHSSO).针对现有PCCR存在的主要问题:限制使用者头部运动和个体标定问题,提出了一种单相机单光源条件下头部位置的补偿方法,实现了头部位置变化对瞳孔角膜向量影响的解析补偿,并建立一种个体差异的转化模型,进而简化标定过程为单点标定.以此为基础形成一种新的视线估计方法,本方法使精确视线估计的最小硬件要求降低到单相机(未标定)单光源,既不需要繁杂的系统标定,又实现了自然头动视线估计,并且简化用户标定为单点标定.该方法的各个环节都满足实时性要求,为面向人机交互的视线追踪系统提供了有效的解决方案.     

预应力管桩施工对场地地震液化的影响

通过对新乡某工程的勘察进行实例分析,详细阐述了预应力管桩施工的挤土效应对场地地震液化的影响,为类似工程提供参考。     

Fabricating of silver and copper nano/microtubes using nano-scale glass fibers as templates

In this paper, large-scale uniform silver and copper nano/microtubes with high length diameter ratios have been successfully synthesized by a facile approach, using low-cost nano-scale glass fibers as templates. The tubular structures can be obtained by reducing of Ag and Cu ions on the surface of the fibers, along with removing the templates. The samples are characterized by SEM and XRD. Results show the tubular structures are very uniform and the tubular walls are composed of densely coalesced crystalline nanoparticles of 30–50 nm.     

国内外盐湖卤水锂资源及开发现状

简要介绍了国内外盐湖锂资源状况及开发现状，并就我国盐湖卤水锂资源的开发提出了建议。     

反应等离子喷涂TiN/AlN涂层的性能研究

TiN涂层可以通过传统的物理或者化学气相沉积（PVD及CVD）工艺制备,但其缺点是沉积速率低,涂层厚度过薄;这些都严重地限制了TiN涂层材料在磨、蚀服役条件下的应用.本文利用反应等离子喷涂的方法制备了TiN/AlN涂层并研究分析了涂层的组织及摩擦磨损性能.结果表明：TiN/AlN涂层韧性比TiN涂层有所提高;TiN/AlN涂层不仅有较低的摩擦系数,且在高载下的磨损性能比TiN涂层有较大的提高.     

IC用引线框架材料QFe2.5合金工艺研究

本文简述了引线框架材料的发展背景及现状,根据后续加工对材料特性和具体性能的要求,介绍了引线框架用铜合金材料的研究机理,重点阐述了QFe2.5引线框架用铜合金带材的合金特性、加热热轧、时效析出退火等工艺技术,同时针对框架材料的加工工艺流程及控制要素进行了研究。     

Ce3+对Er3+的上转换荧光淬灭

提要:本文研究了Ce3 离子对Er3 离子的上转换荧光淬灭规律,随着Ce3 离子浓度增加,Er3 离子各波段的上转换荧光强度迅速下降,并且发现红色荧光带的淬灭要快于绿色荧光带。具体分析了Er3 离子的上转换荧光的产生机制,通过分析Ce3 对Er3 离子淬灭机理,进一步讨论了Er3 离子的上转换机制。     

On the tension necking of copper single crystal specimen under slip deformation mechanism

The tension necking of FCC copper single crystal specimen with a square cross section was analyzed under the slip deformation mechanism. The actual clamp manner of the specimen was modeled by setting correlative boundary condition,and the small angle deflection between tension loading axis and crystallography axis [100] was taken into account. The finite deformation numerical analysis of three-dimensional necking deformation for the specimen was performed by apply-ing crystal plasticity theory associated with a numerical algorithm suggested by the first author. According to the comparison with experimental observation,the fact was confirmed that the numerical results could describe the loading elongation curve of the copper single crystal specimen under large strain tension reasonably,and the method could be used to investigate the necking characteristic in neck shape and the effect due to the small angle deflection. Further,the investigation into the influence of specimen cross-section shape on necking was also performed;the results on mechanical response and neck profile evolution obtained through modeling of cylindrical specimen were compared with those obtained with square cross-section specimen.