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Design of Broadband Compact Canonical Triple-Sleeve Antenna Operating in UHF Band
Chandana SaiRam,Damera Vakula,Mada Chakravarthy 한국전자파학회JEES 2021 Journal of Electromagnetic Engineering and Science Vol.21 No.4
In this paper, a novel compact broadband antenna at UHF frequencies is presented with canonical shapes. Hemispherical, conical and cylindrical shapes have all been considered for antenna configuration. The designed antenna provides an instantaneous frequency range from 370 to 5,000 MHz with omnidirectional characteristics. The antenna was simulated in CST Microwave Studio, fabricated and evaluated; the results are presented. The simulated and measurement results are in good agreement. The antenna has voltage standing wave ratio (VSWR) ≤ 1.9:1 in 400–570 MHz, 2,530–3,740 MHz and 4,180–4,620 MHz; it has VSWR ≤ 3:1 over the operating frequency range 370–5,000 MHz and the measured gain varies from -0.6 to 4.5 dBi over the frequency band. The concept of canonical-shaped antenna elements and the incorporation of triple sleeves resulted in a reduction of the length of the antenna by 62% compared to the length of a half-wave dipole antenna designed at the lowest frequency. The antenna can be used for trans-receiving applications in wireless communication.
REPRESENTATIONS BY QUATERNARY QUADRATIC FORMS WITH COEFFICIENTS 1, 2, 5 OR 10
Alaca, Ayse,Altiary, Mada Korean Mathematical Society 2019 대한수학회논문집 Vol.34 No.1
We determine explicit formulas for the number of representations of a positive integer n by quaternary quadratic forms with coefficients 1, 2, 5 or 10. We use a modular forms approach.
Ana L. Martı´nez-Lo´pez,Elizabeth Carvajal-Millan,Jorge Marquez-Escalante,Alma C. Campa-Mada,Agustı´n Rasco´n-Chu,Yolanda L. Lo´pez-Franco,Jaime Lizardi-Mendoza 한국식품과학회 2019 Food Science and Biotechnology Vol.28 No.2
Arabinoxylans (AX) gels at 4% (w/v) wereprepared using laccase (LAX gels) or peroxidase (PAXgels), and their cross-linking, rheological, structural, andspectroscopic characteristics were investigated. LAX gelspresented lower amount of 5,50-diferulic acid (11%),smaller mesh size (128 nm), and higher hardness (37 N)and elasticity (430 Pa) than the PAX gels (28%, 197 nm,7 N, and 120 Pa, respectively). Microscopy of the LAXgels showed linked strands, while the system was lessconnected in the PAX gels. The Raman band at 2895 cm-1of the LAX and PAX gels was less intense, indicatingenhanced hydrogen bonding compared to that of AX. Thisdecrease was less dramatic for the PAX gels. The greatercontent of 5,50-diferulic acid in PAX gels could favorintrachain bonds, affecting their rheological, structural, andspectroscopic characteristics. Laccase may be a betteroption than peroxidase for AX gelation intended for foodand biotechnological applications.