COMPACT FOUR-COMPONENT 2-D FDFD METHOD WITH EQUIVALENT SURFACE IMPEDANCE BOUNDARY CONDITION FOR MULTILAYER METAL-COATED WAVEGUIDE

A compact four-component two-dimensional （2-D） finite-difference frequency domain （FDFD） method with the equivalent surface impedance boundary condition is used to analyze the dispersion characteristics of multilayer metal-coated waveguides. According to the equivalent surface impedance boundary condition,the relationship between transverse field components on the boundary can be easily depicted. Once the eigen equation is solved,the propagation constant can be obtained as the eigen value for a given frequency. Results of the proposed method agaree well with those of high frequency structure simulator（HFSS）.

ANALYSIS OF DYNAMIC INSTABILITY OF INTERFACIAL SLIP WAVES BASED ON THE SURFACE IMPEDANCE TENSOR

A new method relying on the Stroh formulism and the theory of the surface impedance tensor was developed to investigate the dynamic instability of interfacial slip waves.The concept of the surface impedance tensor was extended to the case where the wave speed is of a complex value,and the boundary conditions at the frictionally contacting interface were expressed by the surface impedance tensor.Then the boundary value problem was transformed to searching for zeroes of a complex polynomial in the unit circle.As an example,the steady frictional sliding of an elastic half-space in contact with a rigid flat surface was considered in details.A quartic complex characteristic equation was derived and its solution behavior in the unit circle was discussed.An explicit expression for the instability condition of the interfacial slip waves was presented.

4-component 2-D CFDFD method in analysis of lossy circular waveguide with fractal rough surface

In this paper, equivalent surface impedance boundary condition （ESIBC）, which takes fractal parameters （D, G） into SIBC, is implemented in the 4-component 2-D compact finite difference frequency domain （2-D CFDFD） method to an- alyze the propagation characteristics of lossy circular waveguide with fractal rough surface based on Weierstrass-Mandelbrot （W-M） function. Fractal parameters’ effects on attenuation constant are presented in the 3 mm lossy circular waveguide, and the attenuation constants of the first three modes vary monotonically with scaling constant （G） and decrease as the fractal dimension （D） increasing.

Study of Mode Coupling on Coaxial Resonators

A study of mode coupling phenomenon of coaxial resonators has been conducted with theories. Through establishing the source-free transmission line equation, boundary conditions of the coaxial resonators with a corrugated inner conductor are analyzed. In the end, calculations are performed in a wide range of corrugation parameters for the resonator of the Karlsruhe Institute of Technology （KIT） relevant coaxial gyrotron.

A NOVEL COMPACT HIS-EBG STRUCTURE AND ITS APPLICATION IN REDUCTION OF PRINTED ANTENNA MUTUAL COUPLING

Anovel compact E shape High Impedance Surface(HIS) Electromagnetic Band-Gap(EBG) comprising Amended Minkowski Fractal Boundary(AMFB),Added Metal Strips(AMS),and metal plated via printed on a Rogers TMM 10i substrate is presented.The first order AMFB and ABS are introduced for equivalent capacitance enhancement and miniaturization with effective space-filling characteristics.The dimension of lattice size is only The proposed structure exhibits a most compact characteristic about 35% size reduction as compared with conven-tional mushroom-like HIS-EBG,and better surface-wave decoupling of around 9 dB at the operating frequency band.Details of design parameters which affect the whole performance of certain band-gap are intensively investigated.A constructed prototype is potential candidate for antenna system per-formance enhancement.

Design of a varactor-tunable metamaterial absorber

In this paper, we design a varactor-tunable metamaterial absorber （MA）. The tunable MA is based on a mushroom-type high impedance surface （HIS）, in which varactors are loaded between adjacent metal patches to adjust the capacitance and tune the resonance frequency, the primary ground plane is etched as the bias network to bias all of the varactors in parallel, and another ultra-thin grounded film is attached to the bottom. Its absorption characteristics are realized for electrically dielectric loss. The simulated values of a sample indicate that a tunable frequency range from 2.85 GHz to 2.22 GHz is achieved by adjusting the varactor capacitance from 0.1 pF to 2.0 pF, and better than 0.97 absorbance is realized; in addition, the tunable frequency range is expanded from 4.12 GHz to 1.70 GHz after optimization.

The specific acoustic impedance of aperture on cylindrical surface

The acoustic impedance caused by sound radiation at the terminals of the aperture on cylindrical surface is analyzed based upon rigorous sound theory. In low frequency range, the approximate solution of the specific acoustic resistance is derived. Special treatments are introduced in order to simplify the solution of the specific acoustic reactance. It is verified that the specific acoustic reactance of such an aperture is equal to that of a similar aperture on the infinitely large plane when the small quantities of high order are neglected.

Construction of Nanophase Novel Coatings-Based Titanium for the Enhancement of Protein Adsorption

In the recent years,biological nanostructures coatings have been incorporated into orthopedic and dental implants in order to accelerate osseointegration and reducing surgical restrictions.In the present work,chemical etching,anodization and metal doping surface modification methods were integrated in one strategy to fabricate innovative titanium surfaces denominated by titanium nanoporous,anodized titanium nanoporous,silver-anodized titanium nanoporous and gold-anodized titanium nanoporous.The stability properties of nanostructures-coated surfaces were elucidated using electrochemical impedance spectroscopy（EIS） after 7 days of immersion in simulated biological fluids.Morphology and chemical compositions of new surfaces were characterized by scanning electron microscope and energy-dispersive X-ray analysis.The EIS results and data fitting to the electrical equivalent circuit model demonstrated the influence of adsorption of bovine serum albumin on new surfaces as a function of protein concentration.Adsorption process was described by the very well-known model of the Langmuir adsorption isotherm.The thermodynamic parameter DGADS（-50 to 59 kJ mol^（-1）） is calculated,which supports the instantaneous adsorption of protein from biological fluids to new surfaces and refers to their good biocompatibility.Ultimately,this study explores new surface strategy to gain new implants as a means of improving clinical outcomes of patients undergoing orthopedic surgery.