RESUMEN
Chemically synthesized PEDOT (poly(3,4-ethylenedioxythiophene)) nanomaterials, with various nanostructured morphologies as well as different intrinsic electrical conductivities and crystallinities, were compared as electrocatalysts for Co(III) reduction in dye-sensitized solar cells (DSSCs). Electrochemical parameters, charge transfer resistance toward the electrode/electrolyte interface, catalytic activity for Co(III)-reduction, and diffusion of cobalt redox species greatly depend on the morphology, crystallinity, and intrinsic electrical conductivity of the chemically synthesized PEDOTs and optimization of the fabrication procedure for counter electrodes. The PEDOT counter electrode, fabricated by spin coating a DMSO-dispersed PEDOT solution with an ordered 1D structure and nanosized fibers averaging 70 nm in diameter and an electrical conductivity of â¼16 S cm-1, exhibits the lowest charge transfer resistance, highest diffusion for a cobalt redox mediator and superior electrocatalytic performance compared to a traditional Pt-counter electrode. The photovoltaic performance of the DSSC using chemically synthesized PEDOT exceeds that of a Pt-electrode device because of the enhanced current density, which is directly related to the superior electrocatalytic ability of PEDOT for Co(III)-reduction. This simple spin-coated counter electrode prepared using cheap and scalable chemically synthesized PEDOT can be a potential alternative to the expensive Pt-counter electrode for cobalt and other redox electrolytes in DSSCs and various flexible electronic devices.
RESUMEN
Photo-rechargeable energy storage devices are appealing for substantial research attention because of their possible applications in the Internet of Things (IoT) and low-powered miniaturized portable electronics. However, due to the incompatibility of the photovoltaics and energy storage systems (ESSs), the overall light-to-storage efficiency is limited under indoor light conditions. Herein, a porous carbon scaffold MnO-Mn3 O4 /C microsphere-based monolithic dye-sensitized photo-rechargeable asymmetric supercapacitor (DSPC) is fabricated. The integrated DSPC has a high areal specific capacitance of 281.9 mF cm-2 at the discharge rate of 0.01 mA cm-2 . The light-to-electrical conversion efficiency of the DSSC is 27.6% under the 1000 lux compact fluorescent lamp (CFL). The DSPC shows an outstanding light-to-charge storage efficiency of 21.6%, which is higher than that reported ever. Furthermore, the fabricated polymer gel electrolyte-based quasi-solid state (QSS) DSPC shows similar overall conversion efficiency with superior cycling capability. This work shows a convenient fabrication process for a wireless power pack of interest with outstanding performance.
RESUMEN
Caseous lymphadenitis (CLA) caused by Corynebacterium pseudotuberculosis is a chronic disease that affects goats. The Korean native goat (KNG) is the most popular goat breed raised in Korea. In this study, the distribution of CLA in the KNG population and the relevance of sex and age in disease development were determined. From March 2020 to February 2021, 1,177 KNGs from 110 farms were assessed. The distribution of CLA in animals was determined by a veterinary inspector who performed gross examinations of goat carcasses and confirmed diagnoses via polymerase chain reaction and bacteriological examination. The CLA detection rate in the KNG population was 19.80%, and more than half of the farms were affected by the disease (56.36%). A statistically significant difference was observed among the sex groups, with castrated males (13.98%) having the lowest detection rate, followed by intact males (22.48%) and females (24.09%), suggesting that castration has a positive effect on reducing the risk of CLA (p < 0.05). In terms of age groups, an increased detection rate of 28.16% was observed in the late adult (>2 years) group. Phylogenetic analysis indicated that the RNA polymerase beta subunit-encoding gene can effectively differentiate biovar ovis from biovar equi and can be used for further epidemiological studies of C. pseudotuberculosis. This is the first nationwide surveillance study of CLA distribution to confirm the continuous occurrence of CLA in Korean goat farms. Future studies should include risk factor analyses of CLA based on herd levels to prevent and control this disease in Korea.
RESUMEN
Uniaxial ferroelectrics with tetragonal tungsten bronze structure are important functional materials with photorefractive, electrooptic, piezoelectric, and pyroelectric properties. SrxBa1-xNb2O6 (SBN100x) with x > 50 is known as a typical uniaxial relaxor ferroelectric, while CaxBa1-xNb2O6 (CBN100x) undergoes nearly normal ferroelectric phase transitions. Single crystals of CSBN100x = [x(CBN28) + (1 - x) (SBN61)] = xCa0.28Ba0.72Nb2O6 + (1 - x) Sr0.61Ba0.39Nb2O6 with nominal x = 0.00, 0.25, 0.50, 0.75, and 1.00 were studied to clarify the dynamical properties at the crossover from relaxor (x = 0) to normal (x = 1) ferroelectric behavior. The longitudinal acoustic (LA) and transverse acoustic (TA) modes and a central peak (CP) related to the relaxation process of polarization fluctuations along the polar c-axis were studied in uniaxial ferroelectric CSBN single crystals as a function of temperature via Brillouin scattering spectroscopy. A CBN28 (x = 1.00) crystal shows the sharp elastic anomaly of the LA mode in the gigahertz range toward Curie temperature, Tc. However, those of CSBN25 (x = 0.25) and SBN61 (x = 0.00) crystals show diffusive anomalies due to stronger random fields. The relaxation time determined from the width of a CP shows a critical slowing down in the vicinity of Tc. The elastic anomaly and slowing down of relaxation time of CSBN100x crystals become diffusive in the vicinity of Tc as the CBN28 content decreases. The origin of the crossover from relaxor to normal ferroelectric phase transitions is discussed in terms of the difference in the A1 and A2 sites' occupancies.
