Transmission properties of frequency selective structures with air gaps

The transmission properties of compound frequency selective structures with dielectric slab and air gaps were investigated by computation and experimentation. Mechanism analyses were also carried out. Results show that the air gaps have a distinct influence on the transmission properties. Resonant frequency of the structure would increase rapidly when the air gap appears. After the gap gets larger to a specific value, generally 1/5 wavelength corresponding to the resonant frequency, the transmission properties would change periodically with the gap thickness. The change of transmission properties in one period has a close relationship with the dielectric thickness. These results provide a new method for designing a bandpass radome of large incidence angle and low loss with the concept of stealth shield radome.

EFFECT OF STRUCTURE OF FUNCTIONAL POLYMER ACTIVE MATERIALS ON PROPERTIES OF GADOLINIUM ION SELECTIVE ELECTRODE

In this paper,the functional polymeric active materials were prepared by the grafting copolymerization and their structure and properties were studied.The results show that the structure and properties of these ac- tive materials have the relative large effects on the properties of gadolinium ion selective electrodes.

POLYMORPH CONTROL OF ANTIMONY WHITE(Sb_2O_3)PREPARED BY HYDROMETALLURGY METHOD

The effects of reaction solvent, the properties of Sb 4O 5Cl 2 material and the ligand additives on the reaction rate and polymorph of antimony white(Sb 2O 3) in the reaction of Sb 4O 5Cl 2 transforming into Sb 2O 3 have been investigated by XRD and IR method. It is revealed that the reaction solvent and the properties of Sb 4O 5Cl 2 are the key factors affecting the reaction rate. The polymorph of antimony trioxides is determined by the reaction mechanism, i.e. the coordination state of the antimony activated complex. Adding a little ligand such as EDTA is the most economical and effective method of synthesizing cubic antimony white(Sb 2O 3)in hydrometallurgical transformation process.

An Orthogonal Least Squares Based Approach to FIR Designs

This paper is concerned with the application of forward Orthogonal Least Squares (OLS) algorithm to the design of Finite Impulse Response (FIR) filters. The focus of this study is a new FIR filter design procedure and to compare this with traditional methods known as the fir2() routine provided by MATLAB.

Reliability Sensitivity-based Correlation Coefficient Calculation in Structural Reliability Analysis

The correlation coefficients of random variables of mechanical structures are generally chosen with experience or even ignored,which cannot actually reflect the effects of parameter uncertainties on reliability.To discuss the selection problem of the correlation coefficients from the reliability-based sensitivity point of view,the theory principle of the problem is established based on the results of the reliability sensitivity,and the criterion of correlation among random variables is shown.The values of the correlation coefficients are obtained according to the proposed principle and the reliability sensitivity problem is discussed.Numerical studies have shown the following results：（1） If the sensitivity value of correlation coefficient ρ is less than（at what magnitude 0.000 01）,then the correlation could be ignored,which could simplify the procedure without introducing additional error.（2） However,as the difference between ρs,that is the most sensitive to the reliability,and ρR,that is with the smallest reliability,is less than 0.001,ρs is suggested to model the dependency of random variables.This could ensure the robust quality of system without the loss of safety requirement.（3） In the case of ｜Eabs｜ρ0.001 and also ｜Erel｜ρ0.001,ρR should be employed to quantify the correlation among random variables in order to ensure the accuracy of reliability analysis.Application of the proposed approach could provide a practical routine for mechanical design and manufactory to study the reliability and reliability-based sensitivity of basic design variables in mechanical reliability analysis and design.

A 3-D Selected Solvent Large Aperture MOF

The metal-organic framework（MOF）{[Cu（L1）_（0.5）（CN）]·4H_2O·3DMSO}_n（1） was assembled by 1,4-bis（3？,5？-dicyano-2？,6？-di（pyrid-4-yl）-1？,4？-dihydropyridyl）benzene（L1） together with copper cyanide at room temperature. In 1,the Cu~＋ ions are linked by CN-anions into a 1D helical chain,which is further fused together by tetradentate L1 ligands to build an extended 3D porous framework with two different types of functionalized channels. 1 crystallizes in the monoclinic,space group P21/c with a = 17.8729（6）,b = 8.7298（3）,c = 22.7524（9） ？,β = 96.072（4）o,V = 3530.1（2） ？~3,μ = 0.845 mm-1,Dc = 1.352 Mg/m^3,Z = 4,Mr = 718.35,F（000） = 1500,S = 1.081,the final R = 0.0877 and wR = 0.2275 for 6975 observed reflections with I 〉 2σ（I）.

Identification and Structure Selection for Nonlinear Stochastic Systems

A nonlinear model is proposed for effective adaptive control design. The model represents a natural way to describe input output nonlinear systems. A combined parameter off line estimation and structure detection algorithm is developed that can use an initial set of data. Then, an efficient model is obtained using orthogonal estimation with an error reduction test and other monitoring modifications. A recursive on line identification scheme is established based on the ELS algorithm to account for future time variations in the process of the parsimonious model.

Continuous selections for pseudo-lower semicontinuous set-valued mappings on convex structure spaces and hyperspace contractibility

SINCE 1956, Michael’s continuous selection theory has been applied to functional analysis,topology, approximation theory and other mathematical fields. In this letter, the concept ofthe pseudo-lower semicontinuity is introduced, and a convex structure of metric space is de-fined. A continuous selection theorem for pseudo-lower semicontinuity is given. This

Model Predictive Control for Vapor Compression Cycle of Refrigeration Process

A model predictive controller based on a novel structure selection criterion for the vapor compression cycle （VCC） of refrigeration process is proposed in this paper. Firstly, those system variables are analyzed which exert significant influences on the system performance. Then the structure selection criterion, a trade-off between computation complexity and model performance, is applied to different model structures, and the results are utilized to determine the optimized model structure for controller design. The controller based on multivariable model predictive control （MPC） strategy is designed, and the optimization problem for the reduced order models is formulated as a constrained minimization problem. The effectiveness of the proposed MPC controller is verified on the experimental rig.