Enhanced photoelectric properties of PbSnSe thin films via quick oxygen ion-implantation sensitization

Journal of Materials Science - Although chalcogenide materials continue to generate considerable interest due to great potentials for various optoelectronic devices, annealing for a long time in...     

Dense and core-rim structured B4C-TiB2 ceramics with Mo-Co-WC additive

B₄C-TiB₂ ceramics (TiB₂ ranging 5~70 vol%) with Mo-Co-WC as the sintering additive were prepared by spark plasma sintering. In comparison with B₄C-TiB₂ without additive, the enhanced densification was evident in the sintered specimen with Mo-Co-WC additive. Core-rim structured grain was observed around TiB₂ grains. The interface of the rim between TiB₂ and B₄C phases demonstrated different feature: the inner borderline of the rim exhibited a smooth feature, whereas a sharp curved grain boundary was observed between the rim and the B₄C grain. The formation mechanism is discussed: the epitaxial growth of (Ti,Mo,W)B₂ rim around the TiB₂ core may occur as a result of the solid solution and dissolution-precipitation between TiB₂ phase and the sintering additive. It was revealed that the fracture toughness increased as the content of TiB₂ content increased, alongside the decreased hardness. B₄C-30 vol% TiB₂ specimen demonstrated the optimal combination of mechanical properties, reaching Vickers hardness of 24.3 GPa and fracture toughness of 3.33 MPa·m^1/2.     

Mechanical Properties of Single-Layer Diamond Reinforced Poly(vinyl alcohol) Nanocomposites through Atomistic Simulation

Low-dimensional carbon nanostructures are ideal nanofillers to reinforce the mechanical performance of polymer nanocomposites due to their excellent mechanical properties. Through molecular dynamics simulations, the mechanical performance of poly(vinyl alchohol) (PVA) nanocomposites reinforced with a single-layer diamond – diamane is investigated. It is found the PVA/diamane exhibits similar interfacial strengths and pull-out characteristics with the PVA/bilayer-graphene counterpart. Specifically, when the nanofiller is fully embedded in the nanocomposite, it is unable to deform simultaneously with the PVA matrix due to the weak interfacial load transfer efficiency, thus the enhancement effect is not significant. In comparison, diamane can effectively promote the tensile properties of the nanocomposite when it has a laminated structure as it deforms simultaneously with the matrix. With this configuration, the interlayer sp³ bonds endows diamane with a much higher resistance under compression and shear tests, thus the nanocomposite can reach very high compressive and shear stress. Overall, enhancement on the mechanical interlocking at the interface as triggered by surface functionalization is only effective for the fully embedded nanofiller. This work provides a fundamental understanding of the mechanical properties of PVA nanocomposites reinforced by diamane, which can shed lights on the design and preparation of next generation high-performance nanocomposites.     

A practical reliability assessment approach and its application for pile-stabilized slopes using FORM and support vector machine

Bulletin of Engineering Geology and the Environment - Many uncertainties exist in pile-stabilized slopes which make their design substantially complicated. In this paper, a first-order reliability...     

电场对竖直矩形微槽群润湿及表面温度的影响

微槽群在热流密度较大时会达到其毛细极限，可通过主动换热方式之一——电水动力学效应对其进行强化。本文为了研究电场对微槽群表面润湿特性和温度分布的影响，采用平板电极提供电场，蒸馏水作为工质，使用高速相机拍摄微槽内液体润湿长度，测量误差为2.97%～7.46%；使用红外热像仪拍摄电场作用下微槽群表面温度分布，测量误差为2.1%～2.39%。热流密度测量误差范围是9.66%～11.11%。结果表明：电场通过驱动微槽内流体向加热区域流动而提升其润湿性能，且较低热流密度下提升更好。因润湿性能的提升，微槽表面温度得以下降。随着电场增强，微槽横向温度分布的“波峰”、“波谷”差别加大，微槽纵向温度明显降低。当热流密度加大时，温降更为显著，1.4W/cm²热流密度、6kV电压下温降可达到30℃以上。温降的增加反映了电场对微槽的强化润湿进一步提升了微槽换热性能，且电场对较高热流情形下的微槽换热有着更为显著的强化效果。     

一种新的解映射算法的推导和实现

本文在一种16QAM,64QAM,256QAM的解映射算法启发下,提出了新的适合32QAM和128QAM的解映射算法,并在此基础上,给出了适合DVB-C接收机的多QAM解映射结构.然后在FPGA中实现和仿真.最后通过比较说明,相对于传统的查找表解映射方法,提出的解映射算法可以明显减少资源使用率.