Improved Efficiency and Stability of Perovskite Solar Cells Induced by CO Functionalized Hydrophobic Ammonium‐Based Additives

Because of the rapid rise of the efficiency, perovskite solar cells are currently considered as the most promising next‐generation photovoltaic technology. Much effort has been made to improve the efficiency and stability of perovskite solar cells. Here, it is demonstrated that the addition of a novel organic cation of 2‐(6‐bromo‐1,3‐dioxo‐1H‐benzo[de]isoquinolin‐2(3H)‐yl)ethan‐1‐ammonium iodide (2‐NAM), which has strong Lewis acid and base interaction (between C?O and Pb) with perovskite, can effectively increase crystalline grain size and reduce charge carrier recombination of the double cation FA_0.83MA_0.17PbI_2.51Br_0.49 perovskite film, thus boosting the efficiency from 17.1 ± 0.8% to 18.6 ± 0.9% for the 0.1 cm² cell and from 15.5 ± 0.5% to 16.5 ± 0.6% for the 1.0 cm² cell. The champion cell shows efficiencies of 20.0% and 17.6% with active areas of 0.1 and 1.0 cm², respectively. Moreover, the hysteresis behavior is suppressed and the stability is improved. The result provides a promising route to further elevate efficiency and stability of perovskite solar cells by the fine tuning of triple organic cations.     

Lactobacillus reuteri CRL1101 beneficially modulate lipopolysaccharide-mediated inflammatory response in a mouse model of endotoxic shock

Lactobacillus reuteri CRL1101 was found to reduce inflammatory and oxidative damage during endotoxic shock induced by lipopolysaccharide (LPS) administration in mice. This beneficial effect was related to the capacity of both the cell structure as well as their secreted products to act synergistically to induce a tolerogenic profile in immune cells. The study supports the idea that, although probiotic microorganisms may exert their beneficial effects due to their well-known ability to modulate intestinal immunity, these effects are not restricted to the gastrointestinal tract. In addition, we demonstrated that the in vitro screening of lactobacilli strains is still a powerful approach to discriminate the potential probiotic bacteria for specific functions that could be later studied in animal models. From the systematic studies reported here, L. reuteri CRL1101, a strain with technological potential usefulness in dairy products, is proposed as novel probiotic candidate for the prevention and control of systemic inflammatory disorders.     

FPGA-based system for effective IQ imbalance mitigation of RF power amplifiers

To provide an adequate signal integrity to a power amplifier (PA), we propose a digital system for the degradation at the transmitter path, and it is implemented on a field-programmable gate array (FPGA) board. The proposed system offers the following features: A -ary quadrature amplitude modulation (QAM) digital signal generation and in-phase/quadrature (IQ) imbalance mitigation, and by default, it performs as a predistortion model extraction from PA-measured data. The simulations and tests provided are performed to effectively verify the PA linearity by using 256-QAM signals. The nonlinearities are predicted as a reliable solution for linearizing the PA from measurements of AM/AM and AM/PM conversion curves. The performance is evaluated in terms of linearity, computation complexity, and FPGA hardware synthesis according to a dependability compliance of digital signal processing. Finally, the model is validated with input/output data observations to linearize the model with a fitting normalized mean squared error (NMSE) of around  dB, a spurious free dynamic range of 40 dBm, and an adjacent channel power ratio reduction by  dBm, for a class-AB broadband radio frequency PA GaN HEMT of 10 W working at 2.34 GHz.     

A PMC-driven methodology for energy estimation in RVC-CAL video codec specifications

In this paper, an energy estimation methodology based on performance monitor counters (PMC) is proposed to estimate the energy consumption of RVC-CAL video codec specifications. The proposed PMC-driven methodology is able to automatically identify the most appropriate events and training data to cover the main application characteristics. In addition, knowledge of the hardware platform employed is not required. Therefore, this methodology can be easily implemented on other PMC-available systems while keeping the estimation accuracy. It is worth noting that this is an attractive asset to analyze the energy consumption of RVC-CAL codec specifications. Besides, the methodology reduces the PMC redundancy and, thus, the overhead introduced when applied to on-line power management. Experimenting on two RVC-CAL decoders, H.264 and MPEG4 Part2 SP, a coarse estimation model based on instructions per cycle (IPC) and the proposed PMC-driven model are compared. The results show that the PMC-driven model can achieve for the H.264 and MPEG4 Part2 SP decoders average estimation errors of 5.95% and 5.01%, respectively, in comparison to the 17.11% and 13.65% average errors obtained with the IPC-based model. As a consequence, this methodology is suggested to be combined into the RVC framework to help the designer to have an overview of the energy consumption of the specification actors at earlier design stages.     

Effect of fcc-hcp phase transformation produced by isothermal aging on the corrosion resistance of a Co-27Cr-5Mo-0.05C alloy

The corrosion resistance of two-phase (fcc-hcp) Co-27Cr-5Mo-0.05C alloys produced by isothermal aging at 800 °C was studied using potentiostatic polarization tests in Ringer’s solution. Critical pitting potentials were estimated from the potentiostatic polarization curves and were found superior to that exhibited by the conventional ASTM-F75 cast alloy used for the manufacture of orthopedic implants. Formation of suitable distributions of hcp embryos (incoherent twin boundaries and stacking faults) prior to and during the early stages of aging required for isothermal fcc-hcp transformation led to a relative reduction of the corrosion resistance of two-phase alloys. However, once the transformation proceeded rapidly, between 4 and 8 hours of aging, the elimination of lattice defects caused a reduction of the dissolution rates and the breakdown potential became nearly independent of the relative amounts of fcc and hcp phases present in the microstructure. This behavior was due to the uniform chemical composition of the two-phase alloys. Concurrent work has shown that the hardness and yield strength of a 50 pct hcp alloy are increased by at least 30 pct without undue ductility losses. Therefore, the results of the present article suggest that these materials are excellent candidates for the manufacture of orthopedic implant devices requiring higher strength than provided by conventional ASTM-F75 materials.     

Tensile Stress Induced Phase Transformations in Zn-Al Alloy

Both furnace cooled and as-cast eutectoid Zn-Al alloys were investigated under external tensile stress at 100℃. It was observed that the external tensile stress caused decomposition of two metastable phases η'T and η'S which derived from both original state of the alloy, and a phase transformation, αf +ε→T' +η, in both furnace cooled and as-cast eutectoid Zn-Al alloys. Also spheroidized structure formed partially during tensile testing. Superplasticity of the alloy has been discussed correlating with the phase transformations and microstructural changes.     

Interaction of Chitosan with mono and di- valent anions in aqueous solution studied by cyclic voltammetry at a water/1,2-dichloroethane interface

The interaction of the cationic polyelectrolyte chitosan (CHI), of different molecular weights, with two anions, picrate (Pi^?) and eosin (Eo^2?), in water was analyzed at pH 2.50 and 5.00. For this purpose the anions transfer current across a water/1,2-dichloroethane interface was employed to quantify anions concentration in absence or in presence of CHI. When CHI was added in increasing amounts to aqueous solutions containing Eo^2? or Pi^?, a gradual decrease in current values was observed, evidencing the binding of the anions to the polymer. This effect was more important at low pH values and for CHI with the highest molecular weight. From the results it is concluded that the interaction Eo^2?-CHI is stronger than the corresponding to Pi^?, probably due to the higher negative charge, and therefore the more pronounced hydrophilic nature of the first anion, which could lead to favour the electrostatic interactions with the cationic polyelectrolyte.