Wireless power transfer (WPT) is the preferred charging method for electric vehicles (EVs) powered by battery and supercapacitor. In this paper, a novel WPT system with constant current charging ...capability for sightseeing car with supercapacitor storage is designed. First, an optimized magnetic coupler using ferrite cores and magnetic shielding structure is proposed to ensure stable power transfer and high efficiency. Compared with the traditional planar shape ferrite core coupler, the proposed magnetic coupler requires lesser ferrite material without degrading the performance of the WPT system. Second, the model of supercapacitor is applied to the WPT system and the relationship between equivalent load resistances of supercapacitor and charging time is analyzed in detail. Then, a Buck converter with proportional integral (PI) controller is implemented on the secondary side to maintain constant charging current for the variable load. Finally, the proposed design is verified by experiments. Constant charging current of 31.5 A across transfer distance of 15 cm is achieved. The peak transfer power and system efficiency are 2.86 kW and 88.05%, respectively.
Display omitted
•The state-of-the-art XGBoost algorithm is chosen as the mapping function of the tensile strength and plasticity.•The important features are ranked, based on the XGBoost model.•The ...key features are selected as variables for improved PSO optimization.•Results are analyzed theoretically, and proven to be effective and reliable.
Exploring the relationships between the properties of steels and their compositions and manufacturing parameters is extremely crucial and indispensable to understanding the science of materials, and subsequently developing new materials. Tensile strength and plasticity, as two important properties of steels, are key to the improvement and optimization of the mechanical properties of steels. In the present paper, we propose an optimization model combining XGBoost algorithm with improved PSO to address the continuous multivariable optimization problem. The main goal is to determine the mapping functions between the tensile strength and plasticity and their influencing factors, based on a diversity of machine learning models such as Linear Regression, SVM, XGBoost, etc. After evaluating the performance these models, we then select the XGBoost model with highest accuracy as the mapping function, which has not been done in previous studies. Moreover, the determined mapping function serves as the fitness value of particle swarm optimization, after which the tensile strength and plasticity optimization with many variables is realized. Finally, the experimental results are analyzed theoretically, and proven to be effective and reliable.
The discovery and identification of novel active sites are paramount for deepening the understanding of the catalytic mechanism and driving the development of remarkable electrocatalysts. Here, we ...reveal that the genuine active sites for the hydrogen evolution reaction (HER) in LaRuSi are Si sites, not the usually assumed Ru sites. Ru in LaRuSi has a peculiar negative valence state, which leads to strong hydrogen binding to Ru sites. Surprisingly, the Si sites have a Gibbs free energy of hydrogen adsorption that is near zero (0.063 eV). The moderate adsorption of hydrogen on Si sites during the HER process is also validated by in situ Raman analysis. Based on it, LaRuSi exhibits an overpotential of 72 mV at 10 mA cm−2 in alkaline media, which is close to the benchmark of Pt/C. This work sheds light on the recognition of real active sites and the exploration of innovative silicide HER electrocatalysts.
Unlike other Ru‐containing compounds whose active sites are Ru sites, the Si sites in LaRuSi function as real active sites. The unusual negative valence Ru in this compound has excessively tight adsorption for hydrogen, according to both theoretical calculations and in situ Raman observations, but the Si sites have excellent hydrogen adsorption properties.
Barium zirconate titanate (BaTi
0.7
Zr
0.3
O
3
) ceramics were prepared via spark plasma sintering (SPS) and conventional solid-state sintering (CS). Both samples exhibited single phase nature as ...confirmed from the X-ray diffraction analysis. Compared with CS sample, more homogeneous microstructure with smaller grain size was observed in the SPS sample, which greatly improved the dielectric strength of BaTi
0.7
Zr
0.3
O
3
ceramics from 40 (CS) to 170 kV/cm (SPS). Although the polarization of SPS sample was lower than that of CS sample under the same applied electric field, the maximum energy storage density was improved to 0.51 J/cm
3
, which was about 4.5 times higher than that of the CS sample (0.12 J/cm
3
). Moreover, finite element simulation on the local dielectric field distribution was carried out, and the effects of microstructure on the dielectric strength were further confirmed.
The use of synonymous codons with varying frequencies has been observed in many species, and the magnitude varies among closely related species and genes within the same genome. Mutational processes ...or natural selective pressures affect this bias. However, a systematic investigation of codon usage pattern for molluscan species and its association with the two factors hasn’t been conducted. In this study, the whole genome codon usage patterns in oyster genome is investigated using the relative synonymous codon usage (RSCU) method, and 17 putative optimal codons were identified, wherein most had either a cytosine (C) or guanine (G) residue at the third position. Results showed that codon bias was positively associated with gene expression levels and breadth. Optimal codons had different mutational bias patterns compared with nonoptimal codons. Moreover, the results show that codon bias is negatively associated with nucleotide diversity. In the oyster genome, the fourfold degenerate codons are affected by different selective pressures, which can be regarded as an evidence that natural selection shapes codon usage patterns. This research will help to understand how natural selection and mutation bias affect codon usage in Mollusca genomes.
Optimizing the hydrogen adsorption Gibbs free energy (ΔGH) of active sites is essential to improve the overpotential of the electrocatalytic hydrogen evolution reaction (HER). We doped graphene‐like ...Co0.85Se with sulfur and found that the active sites are reversed (from cationic Co sites to anionic S sites), which contributed to an enhancement in electrocatalytic HER performance. The optimal S‐doped Co0.85Se composite has an overpotential of 108 mV (at 10 mA cm−2) and a Tafel slope of 59 mV dec−1, which exceeds other reported Co0.85Se‐based electrocatalysts. The doped S sites have much higher activity than the Co sites, with a hydrogen adsorption Gibbs free energy (ΔGH) close to zero (0.067 eV), which reduces the reaction barrier for hydrogen production. This work provides inspiration for optimizing the intrinsic HER activity of other related transition metal chalcogenides.
Graphene‐like Co0.85Se was doped with sulfur, bringing about a reversal in active sites for the electrocatalytic hydrogen evolution reaction (HER) from cationic cobalt sites to anionic sulfur sites. A consequent change in the hydrogen adsorption Gibbs free energy (ΔGH) of the active sites improved the overpotential of the HER.
PurposeTo provide valuable information for scholars to grasp the current situations, hotspots and future development trends of reliability analysis area.Design/methodology/approachIn this paper, ...recent researches on efficient reliability analysis and applications in complex engineering structures like aeroengine rotor systems are reviewd.FindingsThe recent reliability analysis advances of engineering application in aeroengine rotor system are highlighted, it is worth pointing out that the surrogate model methods hold great efficiency and accuracy advantages in the complex reliability analysis of aeroengine rotor system, since its strong computing power can effectively reduce the analysis time consumption and accelerate the development procedures of aeroengine. Moreover, considering the multi-objective, multi-disciplinary, high-dimensionality and time-varying problems are the common problems in various complex engineering fields, the surrogate model methods and its developed methods also have broad application prospects in the future.Originality/valueFor the strong demand for efficient reliability design technique, this review paper may help to highlights the benefits of reliability analysis methods not only in academia but also in practical engineering application like aeroengine rotor system.
•Continuous and pulsed UV-LED irradiations were compared for microbial inactivation.•Equivalent UV fluence was used for comparing the continuous and pulsed irradiations.•Effects of pulse patterns ...including various frequencies and duty rates were investigated.•UV-LED pulsed irradiation achieved comparable inactivation as continuous irradiation.•Pulsed irradiation can help better thermal management for high output UV-LEDs.
Ultraviolet light-emitting diode (UV-LED) is an emerging UV source and has a number of features that do not exist in conventional mercury based UV lamps. One such feature is the ability to turn the radiation on and off with a high frequency, which enables pulsed irradiation with flexible pulse patterns by UV-LEDs. In this study, the inactivation of different microorganisms by continuous and pulsed irradiation was investigated using UV-LEDs, in order to utilize this unique feature to distinguish the effect of pulsation on inactivation, and to explore the potential benefits of UV-LEDs pulsed irradiation for water disinfection. The analysis was based on the equivalent UV fluence between continuous and pulsed irradiation using two types of actinometry techniques (iodide-iodate and ferrioxalate) for UV fluence determination. The disinfection study involved the inactivation of E. coli and coliphage MS2 in laboratory water, as well as E. coli and total coliform in wastewater. The effects of pulse patterns including frequency (i.e., the number of on-off cycles per second) and duty rate (i.e., the percentage of irradiation time in each on-off cycle) on the inactivation effectiveness were also examined for these microorganisms. The results showed comparable inactivation of all the examined microorganisms by 265 nm UV-LED continuous and pulsed irradiation with various pulse patterns under equivalent UV fluence. The findings in this study were compared with those from conventional xenon lamps pulsed irradiation studies, which not only distinguished the role of pulsed UV irradiation on microorganisms inactivation, but also revealed a key feature of UV-LEDs pulsed irradiation with respect to improved thermal management, potentially affecting application of high output UV-LEDs for water disinfection.
With the gradual improvement of individuals' living standards, there has been a concurrent escalation in the consumption of fats and sugars in the daily dietary habits. Consequently, an increasing ...number of individuals are afflicted by hyperlipidemia, a condition that, could elevate blood viscosity, thereby engendering serious complications in a long run. Traditional lipid-lowering medications, such as statins, manifest substantial side effects, thereby imposing a significant metabolic burden on the liver and kidneys. Conversely, antisense oligonucleotides (ASOs) exhibit attributes such as rapid absorption, prolonged efficacy, and minimal side effects. In light of these considerations, a novel ASO was meticulously designed, sebsequently, its efficacy and toxicity assessments were conducted both in vitro and in vivo. The results unequivocally demonstrate the effectiveness and safety of this ASO.
Display omitted
•A potential gene therapy site for hyperlipidemia has been discovered.•ASOs have been synthesized, validated, and tested for toxicity to knock down PCSK9.•ASO52-L96 may contribute to treat seborrheic alopecia.
The structural order in metallic supercooled liquids and glasses is a long-standing issue. Unlike the medium-range order (MRO) which involves at least hundreds of atoms, short-range order (SRO) only ...concerns the central atom and its neighbors, which can be described more easily. Here, we use the molecular dynamics simulation to investigate the SRO in supercooled liquids and glasses of two pure metals Ta and Ni respectively with the body-centered cubic (BCC) and the face-centered cubic (FCC) crystalline lattice and two binary alloys Cu50Zr50 and Ni50Al50 both with a B2 crystalline phase. To compare, a ternary alloy of Cu47.5Zr47.5Al5 is also investigated. Hexagonal closed-packed (HCP) and icosahedron (ICO) clusters are found to dominate the SRO in both supercooled liquids and glasses. As expected, the glass is found more structurally ordered than the supercooled liquid. The glass transition is found to be linked to the kink of the temperature dependence of SRO. The binary system, as the relatively good glass-former, is less structurally ordered than the monatomic system as a poor glass-former, but it is more structurally ordered than the ternary one. These findings have profound implications for understanding the glass transition and designing new metallic glasses.
Display omitted
•The HCP and ICO symmetries dominate the SRO in metallic SCLs and glasses.•The SRO is closely related with the glass transition.•The ICO clusters are not responsible for the glass forming ability.•A good glass former is structurally disordered like liquid.
