磁控溅射沉积薄膜预溅射时间的光谱诊断

利用Omni-λ300系列光栅光谱仪、CCD数据采集和处理系统以及光纤导光系统等构成的等离子体光谱分析系统,实现了实时获取射频磁控溅射过程中等离子体光谱,分别对NiTa,TiAl陶瓷靶,NiAl,TiAl合金靶四种靶材的磁控溅射过程产生的等离子体进行监测,以TaⅡ333.991 nm,NiⅠ362.473 nm,AlⅠ396.153 nm和TiⅠ398.176 nm为分析线,获得了分析谱线强度随时间的变化规律,并以此为依据确定了预溅射时间,同时研究了不同溅射功率和压强对预溅射时间的影响。     

Mixed domain models for the distribution of aluminum in high silica zeolite SSZ-13

High silica zeolite SSZ-13 with Si/Al ratios varying from 11 to 17 was characterized by aluminum-27 and silicon-29 NMR spectroscopy. Aluminum-27 MAS and MQMAS NMR data indicated that in addition to tetrahedral aluminum sites, a fraction of aluminum sites are present in distorted tetrahedral environments. Although in samples of SSZ-13 having high Si/Al ratios all aluminum atoms are expected to be isolated, silicon-29 NMR spectra revealed that in addition to isolated aluminum atoms (Si(1Al)), non-isolated aluminum atoms (Si(2Al)) exist in the crystals. To model these contributions of the various aluminum atoms, a mixed-domain distribution was developed, using double-six membered rings (D6R) as the basic building units of SSZ-13. A combination of different ideal domains, one containing isolated and the other with non-isolated aluminum sites, has been found to describe the experimental silicon-29 NMR data.     

Characterizing unusual metal substrates for gap‐mode tip‐enhanced Raman spectroscopy

In this article, the electromagnetic (EM) field in gap‐mode tip‐enhanced Raman spectroscopy (TERS) is investigated theoretically and experimentally for a range of commonly used and unusual metal and nonmetal substrates. By approaching a metal tip to a substrate, both form a coupled system that confines the EM field created at the tip apex. The influence of the substrate onto the EM field enhancement is observed in a top‐illumination gap‐mode TERS setup for different metal substrates. These include Au, the most commonly used substrate, and also a wide range of rarely or previously unused TERS substrates (Cu, Ag, Al, Pd, Pt, Ni, Ti, Mo, W, stainless steel, Al₂O₃, SiO₂). Self‐assembled monolayers of thiols and brilliant cresyl blue thin film samples are investigated experimentally on nine metal substrates, all showing considerable TERS enhancement. With finite difference time domain and finite element simulations used, the article provides a good estimate of the EM field enhancement for a wide range of substrates for users to estimate how well a substrate of choice will perform in a gap‐mode TERS experiment. The reduction in EM field strength |E²| compared with Au is less than an order of magnitude for many metals (Calculations: Cu 92%, Ag 81%, Ni 53%). This article experimentally shows that a wide variety of conductive substrates can be used, when one is willing to trade a fraction of the EM field enhancement. TERS was seen on all metal substrates including stainless steel, yet quantification was not always possible. These qualitative results were complemented with intensities from calculations. The wider variety of substrates will increase the applicability of TERS and evolve it one step further towards use in standard analytics. Copyright © 2012 John Wiley & Sons, Ltd.     

Wigner dynamics of quantum semi-relativistic oscillator

The integral Wigner–Liouville equation describing time evolution of the semi-relativistic quantum 1D harmonic oscillator have been exactly solved by combination of the Monte Carlo procedure and molecular dynamics methods. The strong influence of the relativistic effects on the time evolution of the momentum, velocity and coordinate Wigner distribution functions and the average values of quantum operators have been studied. Unexpected ‘protuberances’ in time evolution of the distribution functions were observed. Relativistic proper time dilation for oscillator have been calculated.     

The transient scattering mechanism of dipole array with reflector

The transient backscattering mechanisms of a dipole array with reflector have been investigated from different aspects： time-domain, frequency-domain, and combined time-frequency domain, using 4 × 8 dipole arrays with reflector as an example. The data of scattering from the arrays under the incidence of Gaussian pulses are obtained by finite differential time domain method. The influences of the array structural parameters, incident wave parameters, and incident angles on the waveforms, spectrum, and time-frequency representations of the backscattered fields of the arrays are analysed and conclusions are drawn. From these characteristics and conclusions, it is possible to deduce the array structure inversely from the backscattered field.     

氧化锌纳米带中的面缺陷

面缺陷是纳米带中非常普遍和非常重要的一类缺陷。在有些情况下，面缺陷对于高表面能指数面的出现起着决定性的作用。同时。它们可以诱导纳米带沿着特殊的方向生长。面缺陷可以是孪晶或双晶，层错和由杂质原子聚集在特定原子面所形成的间隙原子层。在本文中。利用透射电子显微术，我们将介绍氧化锌纳米带中被发现的几种面缺陷。我们确认了两种孪晶／双晶结构，它们的孪晶面分别是（01^-13）和（^-2112）面。基面层错有I1和I2两种。在大尺寸的纳米带中，I1基面层错可以折叠到（2^110）面形成棱面层错。当少量的In离子掺入氧化锌纳米带后，我们发现伴随着杂质In在基面的聚集，形成了两种倒反畴界。     

基于激光器激射特性的新型应变传感系统

报道了一种基于掺铒光纤激光器瞬态特性的新型应变传感系统.用光纤环反射镜和光纤Bragg光栅(FBG)构成Fabry-Perot线型腔.腔内插入一个长周期光纤光栅(LPG)，其透射谱的中心波长为1574.4nm.FBG的带宽为0.23nm，不受力时其反射波长为1557.98nm，位于LPG的透射谱左沿；当FBG受力时激射波长向长波方向移动，激光通过LPG时透射损耗增大，腔损耗的增加将使激光激射延迟时间增加.因此，应变的大小可以通过激光产生的延迟时间来测量.这种新型应变传感器的分辨率和灵敏度由抽运光脉冲的高、 关键词： 应变传感 光纤激光器 时域测量 光纤Bragg光栅     

Ar2H+ 分子振动光谱的理论计算

基于近期由本组提供的Ar2 H+ 分子的基态势能面 ,应用含时波包演化方法 ,计算了总角动量J =0时的振动光谱 ,并对其中的一些谱峰进行了指认 .与现有的abinitio结果进行比较 ,这个新势能面包含了关于Ar2 H+ 基态的比较正确的信息     

Al原子共振双线跃迁几率实验研究

我们用Nd：YAG脉冲激光烧蚀金属Al靶产生等离子体，利用时间分辨技术摄取Al等离子体辐射时间分辨谱，获得Al原子共振双线辐射谱；通过积分谱线下的面积，计算共振双线强度；根据共振双线强度比，推断Al原子共振双线跃迁几率比，并与理论计算结果比较。结果发现，实验结果与理论计算符合的很好。     

Domain Investigation by the Conventional Bitter Pattern Technique with Digital Image Processing

In the cases of soft magnetic materials or complex domain configurations, investigations of the domain structure by the conventional Bitter pattern technique are generally difficult. It is demonstrated in this paper, referring to the examples of domain images of thin permalloy films and the basal surface of bulk cobalt single crystals, that this problem can be overcome by the application of digital image processing (DIP) system. In particular, the visibility limit in domain observation was expanded by an order of magnitude and high quality domain images could be obtained. Improvements over earlier results were achieved.