Mechanically tunable broadband terahertz modulator based on high-aligned Ni nanowire arrays

We present a mechanically tunable broadband terahertz(THz) modulator based on the high-aligned Ni nanowire(NW)arrays. The modulator is a sandwich structure consisting of two polydimethylsiloxane layers and a central layer of highaligned Ni NW arrays. Our experimental measurements reveal the transmittance of THz wave can be effectively modulated by mechanical stretching. The NW density in arrays increases with the strain increasing, which induced an enhancement in the absorption of THz wave. When the strain increases from 0 to 6.5%, a linear relationship is observed for the variation of modulation depth(MD) of THz wave regarding the strain, and the modulated range is from 0 to 85% in a frequency range from 0.3 THz to 1.8 THz. Moreover, the detectable MD is about 15% regarding the 1% strain change resolution. This flexible Ni NW-based modulator can be promised many applications, such as remote strain sensing, and wearable devices.     

新型路灯节能系统的设计

设计了一种新型的路灯节能照明控制系统。用发光二极管代替实际路灯,制备出了演示系统。该系统包括单片机、红外线感应器和光敏电阻等元器件。随着外界光照强度和人车流量等条件的改变该系统所控制的路灯可以自动调节灯光亮度,以达到节能的目的。如果该路灯控制系统能够投入使用,将会减少许多无谓的能源消耗,为我们国家所倡导的绿色、低碳、环保的生活添砖加瓦。     

Formation of Interfacial Layers in LaAlO3/Silicon during Film Deposition

We have studied the interracial reactions between amorphous LaAlO3 thin films and Si substrates, using high- resolution transmission electron microscopy and x-ray photoelectron spectroscopy. It has been shown that the interracial layer between LaAlO3 film and Si substrate chemical states show that the ratio of La 4d3/2 to Al 2p is SiLaxAlyOz. The depth distributions of La, Si and Al of the interfacial layer remains unchanged with the depth compared to that of the LaAlO3 film. Moreover, the Si content, in the interracial layer gradually decreases with increasing thickness of the interracial layer. These results strongly suggest that the Al element is not deficient in the interracial layer, as previously believed, and the formation of a SiLaxAlyOz interracial layer is mainly due to the diffusion of Si from the substrate during the LaAlO3 film deposition. With the understanding of the interracial layer formation, ones can control the interface characteristics to ensure the desired performances of devices using high-k oxides as gate dielectrics.     

用于长城等古建筑探测的NMR探测器的磁体设计

以万里长城为代表的古建筑是世界瑰宝,更是中华民族的象征和骄傲.本文提出利用便携式核磁共振（NMR）装置来探测研究这类古建筑的建筑材料,在不对其造成损伤的基础上,发掘其隐含的科学、技术和工程相关的丰富信息.为此,作为第一步,设计了适合于探测这类古建筑的便携式单边NMR探测器组合式磁体.该探测器的磁体结构以semi-Halbach为基础,通过不同磁体模块间的组合得到对应移动探测模式、长距离探测模式和均匀磁场探测模式的磁体结构.随后根据优化结果,设计加工了磁体组件,并采用该磁体进行了流体、长城城砖和现代红砖的NMR实验,实测结果与模拟一致.该组合式磁体的优点在于通过不同磁体模块组合,实现了多种探测方式,适用于探测长城等这类古建筑物需要多种探测模式的科学研究.     

原子尺度控制钙钛矿氧化物薄膜的异质外延生长和特性研究

用激光分子束外延,原子尺度控制的外延生长出多种钙钛矿氧化物异质结.X射线衍射和原子力显微镜测量结果表明,在Si基底上生长的SrTiO3和LaAlO3薄膜具有很好的外延结构和取向,其表面达到原子尺度的光滑.YBCO/SrNb0.01Ti0.99O3、La0.9Sr0.1MnO3/SrNb0.01Ti0.99O3(LSMO/SNTO)等异质结,均观测到较好的p-n结I-V特性.首次观测到钙钛矿结构氧化物p-n结电流的磁调制和正巨磁电阻效应,在255K条件下,当外加磁场分别为5×10-4T、1×10-3T、1×10-2T和0.1T时,LSMO/SNTO p-n结的磁电阻变化率ΔR/R0达到:46.7%、59.7%、70.5%和83.4%;当外加磁场为3T时,在100K条件下,在LSMO/SNTO多层p-n异质结上观测465%的正磁电阻变化率.     

硅基集成电路的发展和新一代栅极氧化物材料的研究现状

随着科学技术的进步和集成电路市场日益扩大的需求，硅基集成电路的集成度越来越高，而集成度的提高是以其核心器件金属氧化物半导体场效应晶体管(MOSFET)的特征尺寸逐渐减小为基础的。当栅极Si02介电层的厚度减小到原子尺度大小时，由于量子效应的影响，Si02将失去介电特性，因此必须寻找一种新的高介电常数(high—K)的氧化物材料来代替它。如今世界上许多国家都开展了替代Si02的介电氧化物材料的研究工作。文章介绍了栅极介电层厚度减小带来的影响，栅极Si02介电层的高尺氧化物材料的要求和租选，并对近期高介电常数氧化物材料的研究状况作了简要的介绍和评述。     

NiO/Ni纳米线阵列紫外光电探测器的设计

设计了一种基于MSP430的NiO/Ni纳米线阵列紫外光电探测器。选用MSP430F149单片机作为主控芯片,液晶显示器作为输出端口,具有高光电探测灵敏性的新材料NiO/Ni纳米线阵列为探头,制作了信号采集、信号处理转换以及显示于一体的NiO/Ni纳米线阵列紫外光电探测器。本文NiO/Ni光电探测器以实用、可靠为目的,为研制更完善的光电探测系统奠定良好的基础。     

基于同极联动结构的一种角度/位移电容传感器

基于同极联动原理,通过调节极板正对面积,设计了一种角度、位移连续可调的双参数电容式传感器。实验和理论研究表明,角度测量范围和分辨率为16°和0.16°;位移测量范围和分辨率为10.02 mm和0.1 mm。该传感器具有无可移动部件、成本低、线性度高和分辨率高等优点。     

The third-order optical nonlinearity of the stainless steel doped SrTiO_3 thin film grown by L-MBE

Stainless steel-doped SrTiO3 thin films were fabricated by laser molecular beam epitaxy (L-MBE). Nonlinear optical property of the thin film was measured by the single beam Z-scan technique at the wavelength of 532 nm. Two two-phonon absorption coefficient and nonlinear refractive index were determined to be 9.37 x 10-7 m/W and 1.55 x 10-6 esu, respectively. The merit figure T was calculated to be 1.8, satisfying condition T < 1 for an optical switch. The thin film has a very promising prospect for the applications in optical device.