Microwave Dielectric Properties of CaTiO3-Ca(Al1/2Ta1/2)O3 Ceramics

The microwave dielectric properties of CaTi_1-χ(Al_1/2Ta_1/2)_cHO₃ solid solutions (0.3 ≤χ≤ 0.5) have been investigated. The ceramic samples had perovskite structures similar to CaTiO₃. The partial substitution of Ti₄₊ by a coupled Al₃₊/Ta_s+ permitted improvement of the quality factor Q . The dielectric constant (τ_r) and temperature coefficient of resonant frequency (τ_r) decrease rapidly with an increase of χ. A new high-quality microwave dielectric material was found at χ= 0.46 with σ_r= 46.5, Q f = 27300 GHz, and π_f= 0 ppm/°C. The relationship between microstructures and dielectric properties is presented.     

Robust stability analysis and design method for the fuzzy feedbacklinearization regulator

A robust stability analysis and design method for a fuzzy feedback linearization regulator is presented. The well-known Takagi-Sugeno fuzzy model is used as the nonlinear plant model. Uncertainties and disturbance are assumed to be included in the model structure with known bounds. For these structured uncertainties, stability robustness of the closed system is analyzed in both input-output sense and Lyapunov sense. The robust stability conditions are proposed using multivariable circle criterion and the relationship between input-output stability and Lyapunov stability. Also, based on the stability analysis, a systematic design procedure for the fuzzy feedback linearization regulator is provided. The effectiveness of the proposed analysis and design method is illustrated by a simple example     

Arm movement activity based user authentication in P2P systems

Peer-to-Peer Networking and Applications - User authentication has become an essential security element that enables a wide range of applications in P2P systems for higher security and safety...     

Microwave Dielectrics in the (La1/2Na1/2)TiO3–Ca(Fe1/2Nb1/2)O3 System

Dielectric properties of the system (1 − x)(La_1/2Na_1/2)TiO₃– _x Ca(Fe_1/2Nb_1/2)O₃, where 0.4 # x # 0.6, have been investigated at microwave frequencies. The temperature coefficient of resonant frequency (τ_f), nearly 0 ppm/°C, was realized at x = 0.58. These ceramics had perovskite structure and showed relatively low dielectric losses. A new dielectric material applicable to microwave devices having Q · f of 12000–14000 GHz and a dielectric constant (ε_r) of 59–60 has been obtained at 1300–1350°C for 5–15 h sintering.     

Capital budgeting process for electric power utilities—an analytic hierarchy process approach

Currently, the electric power industry in U.S.A. is undergoing substantial regulatory and organizational changes with respect to market economics as well as pollution. Under these changing circumstances, in this paper, we utilize the concepts of analytic hierarchy process (AHP) and integer programming (IP) to model the capital budgeting process under both finance and pollution considerations. In particular, first we show how a decision maker can simultaneously incorporate the hard-to-quantify factors (pollutants) as well as easy-to-quantify factors (finance factors) into a hierarchy. Next, we show how priority weights derived from the hierarchy can be used to determine the optimal set of projects to be constructed. Also, we show how the entire capital budgeting process can be performed via an illustrative numerical example. It is hoped that the comprehensive, systematic, and consistent approach shown in this paper will provide the electric power utilities an additional decision support tool in their capital budgeting process. © 1998 John Wiley & Sons, Ltd.     

Broad-band erbium-doped fiber amplifier with double-passconfiguration

We demonstrate a broad-band silica-based erbium-doped fiber amplifier (EDFA) with double-pass configuration. The signal gain and noise figure are obtained more than 24 dB and less than 6 dB, respectively, for 1526-1562 nm and 1569-1605 nm. The same signal gain can be achieved with 53% less pump power and 45% shorter erbium-doped fiber length, compared to a conventional parallel type EDFA. Furthermore, the noise figure and power conversion efficiency are improved for the wavelength range     

A Design of Secure Communication Protocol Using RLWE-Based Homomorphic Encryption in IoT Convergence Cloud Environment

Wireless Personal Communications - A super-connected society is emerging in which things and things or people and things communicate with each other through the Internet of Things. Since devices in...     

Raman Spectroscopy of Tetragonal Zirconia Solid Solutions

Raman spectra of tetragonal zirconia were studied for the systems ZrO₂-Y₂O₃, ZrO₂-CeO₂, ZrO₂-Y₂O₃-Nb₂O₅, and ZrO₂-Y₂O₃-Ta₂O₅ There was no change in the Raman bands for tetragonal ziraconia in the ZrO₂-Y₂O₃ system as a function of Y₂O₃ content . On the other hand, in the ternary systems, the Raman lines corresponding to the stretching modes of two sets of cation-oxygen bonds shifted to greater wave numbers as either Nb₂O₅ Contents increased in Y₂O₃-stabilized tetragonal zirconia. This difference was interpreted by local bonding environments of the pentavalent cations, which were supposed to occupy tetrahedral sites in teteragonal zirconia solid solutions.     

Microwave Characteristics of (Pb,Ca)(Fe,Nb,Sn)O3 Dielectric Materials

The dielectric properties of (Pb_{1− x} Ca _x ){(Fe_1/2Nb_1/2)_{1– y} Sn _y }O₃ solid solutions, where 0.4 lessthan equal tox ≤ 0.6, y = 0.05, 0.1, have been investigated at microwave frequencies. The replacement of Fe³⁺/Nb⁵⁺ by Sn⁴⁺ at the B–site of the perov-skite structure considerably improves the loss quality factor Q and does not remarkably affect the dielectric constant epsilon_r and the temperature coefficient of resonant frequency tau_f. The tau_f value of nearly 0 ppm/°C can be realized for x= 0.55. New high-quality dielectric ceramics having epsilon_r of 85.3-89.9,Qf values of 7510-8600 GHz, and τ_f of 0-9 ppm/°C were obtained at 1150°C for 3 h sintering in air. The influence of the sintering atmosphere on dielectric properties was also investigated.