毫米波频段频率选择表面的分析计算

首先介绍了如何用辅助场量的FDTD方法分析计算毫米波波段的频率选择表面,然后给出了一种能快速计算多层FSS频率响应的方法——拟合电路法,并和FDTD计算的结果比较,结果吻合较好。     

声表面波无线传感系统设计

无线和无源化的声表面波传感器适用于许多特殊场合,其测量系统的设计与基于调制解调的无线传感器相比有许多特殊性,在介绍该类型传感器的测量原理的基础上,结合时域采样的延迟线型声表面波无线传感器,分析了无级信道特征、正交相位解调、本振等要素对无线声表面波传感器测量系统的测量产生的影响,为系统设计提供了依据。     

Copper bonded layers analysis and effects of copper surface conditions on bonding quality for three-dimensional integration

In order to achieve copper wafer bonding with good quality, surface conditions of copper films are important factors. In this work, the effects of surface conditions, such as surface roughness and oxide formation on the bond strength, were investigated under different bonding conditions. Prior to bonding, copper film surfaces were kept in the atmosphere for less than 1 min, 3 days, and 7 days, respectively, to form different thicknesses of oxide on the surface. Some copper wafers were cleaned using HCl before bonding in order to remove the surface oxide. Surface roughness of copper films with and without HCl cleaning was examined. Since surface cleaning before bonding removes oxides but creates surface roughness, it is important to study the corresponding bond strength under different bonding conditions. These results offer the required information for the process design of copper wafer bonding in three-dimensional integration applications.     

Template‐Confined Dewetting Process to Surface Nanopatterns: Fabrication,Structural Tunability,and Structure‐Related Properties

Metallic surface nanopatterns are prepared by a template‐confined dewetting process with multiple structural controllabilities. The morphology of the building blocks is homogeneous throughout the surface nanopatterns, as the dewetting process proceeds separately in each bowl. The features of the building units in the surface patterns are highly dependent on the annealing temperature. Importantly, the size and composition of the nanoparticles in the surface nanopatterns can be pre‐calculated and designed by manipulating the thickness of the evaporated metallic films. The heating temperature and composition of the building units influence the surface‐enhanced Raman scattering (SERS) and plasmonic properties, thus tuning the localized surface plasmon resonance peaks over a broad range (from visible to near infrared). The introduction of silver in the gold surface nanopatterns enhances the SERS performance dramatically. This work not only provides a powerful route to fabricate surface nanopatterns, but also supplies a platform to study the mechanism of the complicated dewetting processes of metals.     

Entropy Production and Admissibility of Shocks

In shock wave theory there are two considerations in selecting the physically relevant shock waves.There is the admissibility criterion for the well-posedness of hyperbolic conservation laws.Another consideraztion concerns the entropy production across the shochs.The latter is natural from the physical point of view,but is not sufficient in its straightforward formulation,if the system is not genuinely nonlinear.In this paper we propose the principles of increasing entropy production and that of the superposition of shocks.These principles arc shown to be equivalent to the admissibility criterion.     

Soliton solutions for quasilinear Schrödinger equations, II

For a class of quasilinear Schrödinger equations, we establish the existence of ground states of soliton-type solutions by a variational method.     

Electromagnetic field of a horizontal electric dipole buried in a medium covering one-dimensionally anisotropic medium

The electromagnetic fields of a horizontal electric dipole buried in a medium covering one-dimensionally anisotropic medium are studied. There are three media, one-dimensionally anisotropic medium covered with a dielectric under the air. The electromagnetic field components are complex because of the multiple reflections from the up and down boundaries. The electromagnetic field components between air and one-dimensionally anisotropic medium are given, the trapped surface waves and lateral waves along the dielectric-anisotropic medium boundary are computed. The results have some practical applications in the communication in sea or lake above one-dimensionally anisotropic earth or sediments.     

Characterization of germanium implanted Si1−xGex layer

Characterization of a Si_1−xGe_x layer formed by high-dose germanium implantation and subsequent solid phase epitaxy is reported. Properties of this layer are obtained from electrical measurements on diodes and transistors fabricated in this layer. Results are compared with those of the silicon control devices. It was observed that the germanium implantation created considerable defects that are difficult to eliminate with annealing. These defects result in boron deactivation in the p-type regions of the devices, giving rise to larger resistance. Optimization of the device structure and fabrication process is discussed.     

Synchronous measurements of the atmospheric radio emission in the two and three millimeter wavelength regions

Apparatus and procedure of measuring the atmospheric radio emission simultaneously in two atmospheric windows are described. The results of measurements of the sky brightness temperature and obtained atmospheric optical depth values are reported. The diurnal and seasonal variations of the sky temperature and zenith absorption as well as their relation to weather parameters of nearsurface atmospheric layer are discussed.     

Marked Schottky Groups and Representations of Surface Groups

We give a complete condition for any n elements of PSL(2, R)to generate a Fuchsian group which is a Schottky group on thatset of generators, and apply it to a question of Bowditch onrepresentations of surface groups into PSL(2, R). 2000 MathematicalSubject Classification: 20H10, 32G15.