接触面陷阱密度对a-InSnZnO薄膜晶体管器件电气性能的影响研究

We reported the influence of interface trap density（Nt） on the electrical properties of amorphous InSnZnO based thin-film transistors,which were fabricated at different direct-current（DC） magnetron sputtering powers.The device with the smallest N_t of 5.68×10¹¹ cm^-2 and low resistivity of 1.21×10^-3Ω·cm exhibited a turn-on voltage(V_ON) of-3.60 V,a sub-threshold swing（S.S） of 0.16 V/dec and an on-off ratio(I_ON/I_OFF) of⁸ x 108.With increasing N_t,the V_ON,S.S and I_ON/I_OFF were suppressed to-9.40 V,0.24 V/dec and 2.59×10⁸,respectively.The V_TH shift under negative gate bias stress has also been estimated to investigate the electrical stability of the devices.The result showed that the reduction in N_t contributes to an improvement in the electrical properties and stability.     

Locking‐free discontinuous finite elements for the upper bound yield design of thick plates

This work investigates the formulation of finite elements dedicated to the upper bound kinematic approach of yield design or limit analysis of Reissner–Mindlin thick plates in shear‐bending interaction. The main novelty of this paper is to take full advantage of the fundamental difference between limit analysis and elasticity problems as regards the class of admissible virtual velocity fields. In particular, it has been demonstrated for 2D plane stress, plane strain or 3D limit analysis problems that the use of discontinuous velocity fields presents a lot of advantages when seeking for accurate upper bound estimates. For this reason, discontinuous interpolations of the transverse velocity and the rotation fields for Reissner–Mindlin plates are proposed. The subsequent discrete minimization problem is formulated as a second‐order cone programming problem and is solved using the industrial software package MOSEK . A comprehensive study of the shear‐locking phenomenon is also conducted, and it is shown that discontinuous elements avoid such a phenomenon quite naturally whereas continuous elements cannot without any specific treatment. This particular aspect is confirmed through numerical examples on classical benchmark problems and the so‐obtained upper bound estimates are confronted to recently developed lower bound equilibrium finite elements for thick plates. Copyright © 2015 John Wiley & Sons, Ltd.     

Bichromatic state-insensitive trapping of cold 133Cs–87Rb atomic mixtures

We investigate simultaneous state-insensitive trapping of a mixture of two different atomic species, Caesium and Rubidium. The magic wavelengths of the Caesium and Rubidium atoms are different, 935.6 and 789.9 nm respectively, thus single-frequency simultaneous state-insensitive trapping is not possible. We thus identify bichromatic trapping as a viable approach to tune the two magic wavelengths to a common value. Correspondingly, we present several common magic wavelength combinations appropriate for simultaneous state-insensitive trapping of the two atomic species.     

含硅阻燃大分子相容剂的制备及其在无卤阻燃聚乙烯复合材料中的协效作用

为验证含硅大分子相容剂在无卤阻燃体系中的协效阻燃作用,首先,以马来酸酐、硅橡胶与聚乙烯为原料,通过熔融接枝共聚制备了新型含硅阻燃大分子相容剂;然后,利用氢氧化铝、氢氧化镁和含硅大分子相容剂复配协同阻燃聚乙烯复合材料;最后,探讨了含硅大分子相容剂对复合材料极限氧指数、锥形量热参数、拉伸性能以及微观结构的影响。结果表明:与聚乙烯接枝马来酸酐相比,含硅大分子相容剂含量为10wt%时可使无机阻燃剂在基体树脂中分散较好;随着大分子相容剂含量的增加,复合材料的拉伸强度上升而断裂伸长率下降,极限氧指数提高至34.0%,燃烧时的热释放速率峰值和热释放总量均明显下降,说明含硅大分子相容剂除了能够在该复合材料中起到良好的相容作用外,还可以发挥较好的协效阻燃作用。     

加拿大针叶木纸浆的打浆特性及其电声性能

本文对各种加拿大进口针叶木纸浆的纤维特性做了分析。研究了各种加拿大进口纸浆的打浆特性及其电声性能。结果表明：在加拿大进口纸浆中,电子级乔治王子未漂白硫酸盐木浆FUKP和北木漂白硫酸盐木浆NBKP比较适合做为生产扬声器纸盆的主要材料。在扬声器纸盆的研发过程中,可以根据扬声器的具体用途及对音质的不同要求采用适当比例的FUKP和NBKP混合抄纸来达到相应的目标。     

线性调频信号低旁瓣脉压窗函数的优化设计

由于线性调频(LFM)信号的幅度谱不是标准的矩形形状,常用的窗函数有时无法将脉压旁瓣降得足够低,因此提出了LFM 信号低旁瓣脉压窗函数的优化设计方法。首先,将频域窗函数的求解表示为一个最优化问题,即在保证设计窗函数下的脉压主瓣与期望主瓣的差别小于给定值的条件下,使设计窗函数下的脉压旁瓣尽可能低;然后,将问题表示为标准二阶锥规划形式并求解。仿真实例表明,设计窗的脉压旁瓣显著低于海明窗的脉压旁瓣,设计窗脉压主瓣的无约束部分有所展宽,两个窗函数下脉压信噪比相同。     

非对称双曲面线形离子阱的设计及性能研究

为提升离子阱质量分析器的分析性能,本文提出一种非对称双曲面线形离子阱结构,通过优化离子出射方向上x电极的单向拉伸距离Δr_a,引入合理的非对称射频电场,从而提高离子单向出射效率。利用SIMION和AXSIM模拟软件分析非对称双曲面线形离子阱的内部电场分布、离子运动轨迹及模拟质谱图。结果表明,在性能优化的对称双曲面线形离子阱结构的基础上,其中1个x电极单向拉伸Δr_a=0.8 mm时,通过优化AC频率和扫描速率等参数,非对称双曲面线形离子阱的离子单向出射率可达90%以上,同时m/z 609离子的质量分辨率超过5 100。经优化几何结构后的非对称双曲面线形离子阱可在保证高质量分辨率的情况下,大幅提高离子检测效率,这在小型化质谱仪的开发中具有显著的优势。     

Stormwater quality associated with a silt trap (empty and full) discharging into an urban watercourse in Scotland

The aim was to assess the influence of a full silt trap at the end of a stormwater drainage pipe on the water quality of stormwater discharged into a semi‐natural urban watercourse. For approximately eleven weeks, the water qualities of the preliminarily treated stormwater and of the receiving watercourse (Braid Burn) were studied. The mean outflow concentrations of suspended solids were 2.0 mg/l and 34.1 mg/l during dry and wet weather conditions, respectively. Suspended solids concentrations of up to 141.6 mg/l were recorded during storm events. Suspended solids values for treated stormwater were often too high compared to international secondary wastewater treatment standards of around 30 mg/l. Pollutants including heavy metals (e.g., zinc, copper and nickel) accumulated in the silt trap. However, high outflow velocities during heavy rainfall events did not result in clearly defined sediment layers due to sediment re‐suspension. Metals did not accumulate in the receiving watercourse.     

锚栓群锚抗拉性能试验研究

通过对膨胀型锚栓、扩底型锚栓、普通化学锚栓及特殊倒锥型化学锚栓进行单锚、两锚、四锚和八锚的抗拉试验,研究了群锚抗拉的破坏模式及受力性能,并对群锚受拉承载力的试验值与计算值进行了比较分析.结果表明,锚栓群锚抗拉破坏状态主要有:混凝土锥体破坏、锚栓钢材破坏,承载力试验值与《混凝土结构后锚固技术规程》计算值基本吻合.