MnO纳米粒子的制备及其电催化性能的研究

用微乳液法合成了MnO纳米粒子，探讨了影响萃取率及粒度的因素，得到了最佳反应条件，并用透射电子显微镜(TEM)、X射线衍射仪(XRD)及红外光谱(FTIR)进行了表征。得到了粒径为5nm左右的MnO纳米粒子，并在质子交换膜燃料电池(PEMFC)的铂电极中加入5nm左右的MnO纳米粒子作为催化剂，改变了电池的放电机理，提高了输出电压。为PEMFC的商品化进行了有价值的探索。     

A revisited generalized self-consistent polycrystal model following an incremental small strain formulation and including grain-size distribution effect

A generalized self-consistent approach, recently proposed by Jiang and Weng (2004) [B. Jiang, G.J. Weng, A generalized self-consistent polycrystal model for the yield strength of Nanocrystalline materials, Journal of the Mechanics and Physics of Solids 52 (2004a) 1125-1149; B. Jiang, G.J. Weng, A theory of compressive yield strength of nano-grained ceramics, International Journal of Plasticity 20 (2004b) 2007-2056.] for investigating the so-called “breakdown” of the Hall-Petch law in the case of nanocrystalline (NC) materials, is revisited and reformulated following an incremental small strain scheme. The NC material is modelled as a composite material that takes each oriented grain and its immediate grain boundary to form a pair, which in turn is embedded in the infinite effective medium with a property representing the average orientation of all these pairs. The plastic deformation of the inclusion phase takes into account the dislocation glide mechanism whereas boundary phase is modelled as an amorphous material. As an application, the model’s parameters are identified under an optimization code with respect to data stated from pure copper submitted to tensile load. The aggregate is composed of spherical randomly distributed grains with a grain-size distribution following a log-normal statistical function.     

Effect of Pre-heat and Inert Gas Species on Cryogenic Aerosol Cleaning Performance in Semiconductor Manufacturing

Cryogenic aerosol cleaning is a dry cleaning method used in the back end of line (BEOL) semiconductor manufacturing to remove defects from planar hydrophobic surfaces such as SiCOH and SiCxNyHz. Cryogenic aerosol cleaning is preferred over conventional wet cleaning methods as it is a non-contact cleaning method, which uses inert gases to generate sub-micrometer-sized solid aerosol particles that physically remove nanometer-sized contaminants on wafer surfaces. Particle removal mechanism involves detachment of the particles upon impact with aerosol, diffusion, and finally entrainment away from the wafer. In BEOL metal line patterning, particles on the dielectric isolation surfaces translate through the subsequent lithography and copper fill steps in to single or multiple metal line open defects that are yield killers. In this study, we show that the particle removal performance of the standard aerosol cleaning can be enhanced by pre-heating the wafer and use of a higher molecular weight inert gas, namely Ar, for aerosol generation. Both the addition of a Pre-heat step and the use of Ar as the aerosol source showed 47–52% reduction in single and multiple line opens detected through wafer electrical tests during high volume semiconductor manufacturing process.     

可控性的双层粒子刚体脆性破裂模拟动画

提出一种可控性的双层粒子模型的刚体脆性破裂动画的模拟框架.首先,使用接触力学分析撞击时固体内部产生的弹性位移并采用光滑粒子流体动力学进行离散求解,在此基础上建立一个可控性的内力分析模型.其次,提出一种双层粒子模型来对刚体进行建模,在保证内力计算精度的同时提高了刚体动力学中碰撞检测的效率.最后实现了多个刚体脆性模型场景的动画.该算法可适用于刚体脆性破裂模拟的动画应用.     

GPU‐assisted real‐time coupling of blood flow and vessel wall

The vessel wall and the blood flow interact and influence each other, and real‐time coupling between them is of great importance to the virtual surgery as well as the research and diagnosis of vascular disease. On the basis of smoothed particle hydrodynamics (SPH), we present a new approach to solve non‐Newtonian viscous force of blood and a parallel mixed particles‐based coupling method for blood flow and vessel wall. Meanwhile, we also design a proxy particle‐based vessel wall force visualization method. Our method is as follows. Firstly, we solve the non‐Newtonian viscous forces of blood through the SPH method to discretize the Casson equation. Secondly, in each time step, we combine blood particles and sampling proxy particles on the blood vessel wall to form mixed particles and calculate the interaction forces through the SPH method between every pair of the neighboring mixed particles inside the graphics processing unit. Thirdly, the forces of the proxy particles will be mapped to the color display of the proxy particle. Experimental results demonstrate that our method is able to implement real‐time sizeable coupling of blood flow and vessel wall while mainly ensuring physical authenticity and it can also provide real‐time and obvious information about vessel wall force distribution. Copyright © 2015 John Wiley & Sons, Ltd.     

Homochirality of Organic Matter – Objective Law or Curious Incident?

Of the many hypotheses on the origin of biological homochirality on the Earth, the combination of the notion of subatomic particles composing a homochiral pool of primary matter, on the one hand, with the suggestion of the synthesis of chiral organic molecules in the plasma torch generated by super-high-velocity impacts (SHVI) of meteorites, on the other hand, was chosen as the working assumption.     

填充银纳米线各向同性导电胶的性能

以Ti (OC₄H₉)₄ 水解形成的溶胶体系为模板, 以AgNO₃ 为银纳米线的前驱体, 低温下合成长径比为50～60 的银纳米线, 采用TEM 和XRD 对所制得的银纳米线进行表征。以银纳米线作为导电胶的导电填料, 成功制备了一种高电导率的各向同性导电胶。导电胶的电学性能和力学性能测试表明: 这种导电胶在导电填料含量为56 wt %时的电导率比填充75 wt %微米银粒子的导电胶高约6 倍(体积电阻率为1. 2 ×10-4Ω·cm) 。由于填料含量的降低, 该导电胶的抗剪切强度(以Al 为基板时的抗剪切强度为17. 6 MPa) 相比于填充75 wt %微米银粒子和75 wt %纳米银粒子导电胶均有不同程度的提高。      

纳米态电极催化材料Au-Pt/半胱氨酸/Au电极的制备及性能研究

利用自组装技术制备了纳米态Au-Pt/半胱氨酸/Au电极,TEM、ED、XPS等研究表明双金属纳米粒子为Au合金,粒子的平均粒径＜10nm;通过组装时间可以控制双金属纳米颗粒组装的数量.对组装电极的电化学性能进行了测试,通过SEM对其表面结构进行了表征.结果表明,利用自组装方法可以制备纳米态Au-Pt/半胱氨酸/Au电极,该电极具有良好的电催化性能.