三种纵向结构的AlGaN/GaN HFET性能比较

对AlGaN/GaN HFET纵向的常规结构、倒置结构和双异质结进行了研究,结果表明:常规结构的材料生长简单、容易控制,倒置结构的直流性能低于常规结构,而双异质结虽然在材料生长方面较为复杂,但它可以获得较常规结构更为优良的直流特性.     

Growth-induced magnetic anisotropy in YIG

YIG film were grown by LPE and the substrate was carefully removed by grinding. From the⁵⁷Fe Moessbauer spectrum the orientation of magnetization was determined and the growth-induced magnetic anisotropy constant deduced. For (111) orientation YIG, the magnetic uniaxial anisotropy constant Ku was determined to be 2.3×10³ erg cm^–3.     

利用AFM动态电场在Si表面实现纳米氧化结构

讨论利用原子力显微镜(AFM)动态电场诱导阳极氧化作用下Si表面生成纳米氧化结构的特征,并进行相应的机理分析.实验表明,直流电压作用下的氧化结构表现出单峰特征,而电压脉冲和连续方波所得到的氧化结构具有中央凹陷特征和较高的纵横比.     

An X‐shaped π‐conjugated polymer comprising of fluorene units and anthracene units with high efficiency. Synthesis and optical and electrochemical properties

A new X‐shaped π‐conjugated monomer comprising of fluorene units and anthracene units was synthesized, and it was used to fabricate the new X‐shaped π‐conjugated polymers and investigate the properties of the new polymers. Using different molar ratios between such monomer and a fluorene monomer gave three polymers that showed higher absolute PL quantum yields than the linear polyfluorene (PF) in the solid state. After thermal annealing at 200 °C for 4 h, the linear PF showed an additional bathochromic emission at about 550 nm, whereas such red‐shifted emission was fully eliminated for the X‐shaped polymers. The electroluminescent devices based on the X‐shaped polymers with a configuration of ITO/PEDOT:PSS/polymer/LiF/Ca/Al displayed blue emission with low turn‐on voltage and high brightness. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 5616–5625, 2008     

同构系统的多主体模型构造方法

多主体系统构造的基础是确定主体和主体间的关系，文章提出了一种从业务流程出发的多主体信息系统构造方法，通过对每一项业务流程的分析，得到局部的多主体系统模型；应用有向图生成方法，综合得到整个系统的多主体模型；并讨论了其一致性和完备性的检验。     

Design, synthesis, and biological evaluation of a dansyled amino acid derivative as an imaging agent for apoptosis

To develop a small molecule-based biomarker for in vivo apoptosis imaging, a dansyled amino acid derivative (BNSBA) was designed and synthesized in good yield. The biological evaluation demonstrated that BNSBA selectively binds to apoptotic cancer cells and is localized within the cytoplasm of cells that bound annexin V on the plasma membrane.     

Study of a printed circular disc monopole antenna for UWB systems

This paper presents a study of a novel monopole antenna for ultrawide-band (UWB) applications. Printed on a dielectric substrate and fed by a 50 /spl Omega/ microstrip line, a planar circular disc monopole has been demonstrated to provide an ultra wide 10 dB return loss bandwidth with satisfactory radiation properties. The parameters which affect the performance of the antenna in terms of its frequency domain characteristics are investigated. A good agreement is achieved between the simulation and the experiment. In addition, the time domain performance of the proposed antenna is also evaluated in simulations.