High Step-Up Resonant DC/DC Converter With Balanced Capacitor Voltage for Distributed Generation Systems

Abstract

Telomere length is a biomarker of cell aging that is hypothesized to contribute to women's greater longevity. Although most previous studies have found no sex difference in telomere length at birth, it is well established that females have longer average telomere length than males during adulthood. Proposed biological mechanisms underlying sex differences in adult telomere length include differences in sex steroid hormones and body size, which emerge during the pubertal transition. The purpose of this study was to examine the total effect of sex on telomere length during early adolescence and to examine estradiol, total testosterone, and body surface area (BSA; a measure of body size) as potential mediators of sex differences in telomere length. Data were from a population-based sample of 126 female and 109 male Hispanic adolescents aged 8 to 14 years from the Early Life Exposures in Mexico to ENvironmental Toxicants (ELEMENT) study. Relative telomere length (T/S ratio) was measured by the quantitative polymerase chain reaction method; sex steroid hormones were measured using an automated chemiluminescent immunoassay, and BSA was calculated using measured height and weight. Adjusting for age and pubertal status, we found that girls had significantly longer telomeres than boys (b ¼ .13; P < .01), but there were no significant indirect effects of sex on telomere length through any of the proposed mediators. We conclude that sex differences in telomere length are evident during early adolescence but are not explained by cross-sectional differences in sex steroid hormones or body size.

High voltage gain resonant DC-DC converter with vm cells for renewable sources applications

“…[ The converter proposed in [14] employs the secondary side resonance on the active clamp flyback converter to reduce root-mean-square (RMS) current values to enhance the performance of the synchronous rectifier [13]. The study conducted in [14] uses fewer semiconductor devices in which power is transferred to the output once the main switch becomes off.…”

“…Therefore, the switching loss decreases due to the resonant converter's soft switching. Resonance phenomena enable converters to have high frequency switching, increasing the converter's control system bandwidth, power density, and reduction in overall sizing [13,14]. Connecting the rectifiers' multiple outputs in series can also culminate in high voltage gain [15].…”

Wide Range Series Resonant DC-DC Converter with a Reduced Component Count and Capacitor Voltage Stress for Distributed Generation

“…The converter with a wide input voltage regulation range could be capable of tracking the maximum available power of the PV module in various environmental and shading conditions. One of the promising candidates for this purpose is resonant converters like LLC [4][5][6] and the series resonant converter (SRC) [7][8][9], which are used in many industrial applications. However, LLC employs frequency modulation to regulate the voltage variation, and thus the design of the magnetic component becomes costly and complicated.…”

Three‐phase interleaved high step‐up bidirectional DC–DCconverter

“…Bidirectional DC–DC converters are in great need in the wind, photovoltaic and energy storage systems [4–7]. High conversion ratio DC–DC converters are required in the areas of battery charge, electric vehicles, generation systems and photovoltaic systems [8–13]. In some applications which do not need isolate, non‐isolated bidirectional DC–DC converters have received extensive attention due to its good features [14, 15].…”