SHS法合成低游离硅亚微米级β-Si3N4研究

本文采用SHS工艺对低游离硅(Sif＜1 %)亚微米级β-Si3N4的制备进行了研究,在研究中采用细硅粉团粒作为原料,试验结果表明用团粒为原料合成的β-Si3N4粒度为0.71 μm时,其游离硅含量为0.65 %,而采用常规的硅粉为原料时,当β-Si3N4粒度为0.69 μm时,游离硅的含量高达1.98 %.     

燃煤电厂烟气脱硫石膏综合利用途径及潜力分析

随着火电厂烟气脱硫产业迅猛发展,脱硫石膏产量增长迅速,预计到2010年末,全国年产脱硫石膏将达850万t左右,脱硫石膏综合利用将直接影响火电厂经济效益和环境效益。介绍日本、欧洲、美国等国家烟气脱硫石膏生产与综合利用历史、现状及开展脱硫石膏综合利用的经验与教训,介绍我国典型火电厂烟气脱硫系统FGD石膏生产和综合利用现状。综合考虑发达国家经验教训和中国脱硫产业发展趋势等因素,对未来中国烟气脱硫石膏生产潜力及其可能的利用途径进行分析。天然石膏资源丰富,脱硫石膏综合利用相关法规、政策不健全,缺乏相应的行业标准和技术保障及公众参与意识尚需提高等是影响我国脱硫石膏有效综合利用的主要障碍。     

LASER LIFT-OFF OF GaN THIN FILMS FROM SAPPHIRE SUBSTRATES

1. IntroductionRecently the development of GaN-based blue and blue-green light-emitting devices hasproceeded rapidlyl1] t which will enable the appllcation of b1ue light-emittil1g diodes (LED3)and laser diodes (LDs)l']. However, due to lack of the native substrates, films of GaN areusually grown on dissimilar substrates such as sapphire and SiCl3l4]. The most commonlyused growth substrate, sapphire, still restricts the quaJity of GaN film due to the latticeand thermaLexpansion coefficien…     

Manipulating surface states in topological insulator nanoribbons

Topological insulators display unique properties, such as the quantum spin Hall effect, because time-reversal symmetry allows charges and spins to propagate along the edge or surface of the topological insulator without scattering. However, the direct manipulation of these edge/surface states is difficult because they are significantly outnumbered by bulk carriers. Here, we report experimental evidence for the modulation of these surface states by using a gate voltage to control quantum oscillations in Bi(2)Te(3) nanoribbons. Surface conduction can be significantly enhanced by the gate voltage, with the mobility and Fermi velocity reaching values as high as ~5,800?cm(2)?V(-1)?s(-1) and ~3.7?×?10(5)?m?s(-1), respectively, with up to ~51% of the total conductance being due to the surface states. We also report the first observation of h/2e periodic oscillations, suggesting the presence of time-reversed paths with the same relative zero phase at the interference point. The high surface conduction and ability to manipulate the surface states demonstrated here could lead to new applications in nanoelectronics and spintronics.     

影响恶性肿瘤预后的几种因素

近年来,许多癌症的发病率呈上升趋势,有些人更是淡癌色变,似乎只是要得了癌症其生命便走向了尽头。其实不然,影响癌症预后有诸多因素,因而了解一些相关知识很有必要。     

酸雨对水陆生态的影响

酸雨是当代严重的环境问题之一，它被称为“空中死神”，对水陆生态及水资源危害较大。本文对欧美受酸雨危害的一些国家自本世纪60年代初期至80年代末期花费巨资研究酸雨对水陆生态和水资源危害的成果作了综述。同时对我国酸雨现状和发展趋势以及酸雨对水陆生态危害程度作了简要的介绍。目的在于引起人们重视由酸雨产生的环境问题，并采取有效措施控制酸雨的发展。     

一起110kV变压器有载调压开关故障分析

针对一起在运110 kV变压器有载调压开关故障,对故障设备进行试验、吊罩分解检查,分析出事故产生的原因为绝缘老化相间短路放电造成的选择开关触头不到位,并阐述了故障的处理方案及防范措施,确保有载调压开关的安全稳定运行。     

6通道后向散射仪

6通道后向散射仪是用于海洋光学调查的仪器,可用于测量海水的后向散射系数.本文详细介绍了该仪器的配置、技术参数和使用方法.初步分析了利用该仪器于2005-06在渤海海域进行调查获得的数据,结果显示该仪器可适用于我国近海二类水体的测量.这对于我国近岸水体的光学调查及研究具有极其重要的意义.