Surface analyses of corona-treated poly(ethylene terephthalate)

Poly(ethylene terephthalate) (PET) Mylar® samples were treated by corona discharge in order to improve their adhesive properties. The corona treatments were performed in different atmospheres including nitrogen, ammonia and air. X-ray photoelectron spectroscopy (XPS) was used to investigate the chemical modifications induced at the PET surface by these corona treatments. XPS results show that nitrogen incorporation takes place in the form of non-oxygenated nitrogen functionalities, like amine or cyano groups. These are present at the surface of all the corona-treated samples but in different concentrations depending on the gases used in the corona discharge. Furthermore, XPS analyses performed after heating of the treated samples show a higher thermal stability of the corona-induced surface modifications in the case of nitrogen and ammonia. Ion scattering spectroscopy (ISS) and static secondary ion mass spectroscopy (SIMS) analyses were also performed because of their higher surface sensitivity compared with XPS: ISS reveals that nitrogen is not present at the topmost surface layer of the treated samples but is incorporated just beneath. The outermost surface layer presents a composition rich in oxygen. Finally, static SIMS spectra show that corona treatment induces more surface degradation when performed in air compared with nitrogen or ammonia. These results are discussed in relation to adhesive properties of PET.     

Nucleation of ZnTe on the As-Terminated Si(112) Surface

We employ a suite of surface analysis techniques that probe the outermost ZnTe/As-Si(112) surface to generate an understanding of the initial stages of the heteroepitaxial HgCdTe/CdTe/ZnTe/As-Si(112) layer formation. Ion scattering spectroscopy (ISS), reflection-high energy electron diffraction (RHEED), along with nondestructive depth profiles by angle-resolved x-ray photoelectron spectroscopy (XPS) are successfully applied to clarify and support the nucleation stages of ZnTe formation on the As-terminated Si(112) substrate. Data indicate a slow growth of the first ZnTe layer. In addition, no evidence of thick ZnTe island formation exists. The current ZnTe formation process generates full coverage on the Si(112) surface after six to nine MBE cycles. In order to fully understand the details of the ZnTe nucleation process on the Si(112) substrate, we present an inelastic background analysis with the Tougaard method to study surface morphology.     

一种基于ISS的软硬件协同验证环境

讨论了一种面向SOC设计的基于指令级仿真器(ISS)的软硬件协同验证环境。在该环境中,硬件用硬件描述语言来建模,软件用编程语言来编写,使用指令集仿真器和事件驱动逻辑仿真器分别完成对软硬件的仿真,两个仿真过程使用不同的进程并行进行,并通过进程间通信(IPC)实现两个仿真器之间的信息交互。     

一类非线性系统的鲁棒H∞控制

研究一类可部分反馈线性化且具扰动三角结构的非线性参数不确定系统的鲁棒H∞控制问题,不确定参数属于已知紧集并以非线性形式进入系统.在输入到状态稳定的理论框架下,基于李雅谱诺夫函数和反演法构造出状态反馈控制器,使得闭环系统对所有允许的参数不确定性是内稳定的,且从扰动输入到输出有有界的L2-增益.控制器的设计不需解任何H am ilton-Jacob i方程,并给出仿真算例说明了该结论的可行性和有效性.     

Full-order impulsive observers for impulsive systems with unknown inputs

This paper studies full-order impulsive observers for impulsive systems with unknown inputs. Two types of full-order impulsive observers are designed respectively. The first type is Luenberger-type impulsive observer (LIO). The second type is for the observed system with eliminable unknown input, where the impulsive observer is allowed to have nonidentical dynamic structure with the observed system. The conditions via the average dwell time technique are derived for the existence of these two types of impulsive observers. It is shown that in the LIO, the observer's state tracks the observed system's state in the sense of input-to-state stability (ISS). Specifically, the observer's state track completely the observed system's state if the unknown input trends to zero. While in the second type of impulsive observer, the observer's state tracks completely the observed system's state regardless of the unknown input trends to zero. Finally, three examples with simulations are presented to demonstrate the effectiveness of the theoretical results.