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[IEEE 2018 19th International Conference of Young Specialists on Micro/Nanotechnologies and Electron Devices (EDM) - Erlagol (Altai Republic), Russia (2018.6.29-2018.7.3)] 2018 19th International Conference of Young Specialists on Micro/Nanotechnologies and Electron Devices (EDM) - Use of Genetic Algorithm and Evolution Strategy when Revealing the Worst Case Effects of Crosstalk Propagation in PCB Bus of Spacecraft Autonomous Navigation System
摘要： Importance of the genetic algorithm (GA) and evolution strategy (ES) usage in the investigation of an ultrashort pulse peak voltage in a printed circuit board (PCB) bus of autonomous navigation system (ANS) is highlighted. Trapezoidal ultrashort pulse propagation along the conductors of the PCB bus was optimized. The optimization was made by maximization criteria of maximum crosstalk amplitude at the preset point. The two methods were used for the optimization, which results are compared. The ES optimization was run 20 times when the initial solution was 300 ps. The GA optimization was run 10 times with the parameters: the number of chromosomes – 5, 10; the number of populations – 5, 7, 10, 15; mutation coefficient – 0.1; crossover coefficient – 0.5. After the ES and GA optimizations the crosstalk maximums of 32% and 78% of steady state level in the active conductors respectively were revealed and localized.
关键词： evolution strategy,printed circuit board,ultrashort pulse,genetic algorithm,optimization,peak voltage
更新于2025-09-04 15:30:14
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Tuning Nitrogen Content in Graphitic Carbon Nitride by Isonicotinic acid for Highly Efficient Photocatalytic Hydrogen Evolution
摘要： Graphitic carbon nitride (CN) with various nitrogen contents can be prepared to regulate its electronic structure and energy band levels. The newly-prepared graphitic carbon nitride manifests high photocatalytic activity. In this work, nitrogen-rich CN (CN-NR100) and nitrogen-deficient CN (CN-ND500) were prepared by tuning nitrogen contents in CN while using isonicotinic acid (IA) as an additive in the precursors. It is found that IA reacting with urea can introduce its nitrogen to CN, while reacting with CN can take away the amino group of CN, thus reduces its nitrogen content. Interestingly, the gas that comes from the decomposition of IA is essential for the formation of porous morphology in CN. Both CN-NR100 and CN-ND500 can provide more photocatalytic sites, narrow bandgaps to enhance the absorption of visible light and significantly improve the charge carrier separation efficiency. Therefore, CN-NR100 and CN-ND500 manifest an excellent photocatalytic hydrogen evolution rate of 73 μmol h-1 (about 4 times of that of CN) and 120 μmol h-1 (6.7 times of that of CN), respectively. This work provides an efficient strategy to prepare CN with different nitrogen contents by pyrolysis of precursors modified by IA for high photocatalytic hydrogen evolution.
关键词： Graphitic carbon nitride,Nitrogen content,Isonicotinic acid,Hydrogen evolution
更新于2025-09-04 15:30:14
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Numerical Investigation on the Transient Evolution Mechanisms of Nonlinear Phenomena in a Helium Dielectric Barrier Discharge at Atmospheric Pressure
摘要： In this paper, the evolution and transition mechanisms of typical nonlinear phenomena in an atmospheric pressure helium dielectric barrier discharge (DBD) are investigated from the perspective of transient evolution properties through fluid modeling. By gradually up-regulating the interelectrode gap width, the discharge (steady state) evolves from symmetric single-period (SP1), through asymmetric single-period (AP1), into Period-2 (P2) state. Similar evolution trace can also be obtained when increasing the driving frequency. Right after the initial breakdown, the discharge goes through several transient periods featuring unstable asymmetric current pulses before the establishment of steady-state discharge. As the bifurcation parameter increases in excess of the critical value, the discrepancy between the seed electron level of positive and negative discharges accumulates over the transient periods, switching the discharge into AP1 state. After then, a further elevation in the gas gap width (or driving frequency) leads to the generation of a “moderate intensity” positive pulse. With the “moderate intensity” positive pulse and a stronger positive pulse emerging alternatively in the temporal waveform sequence, the discharge evolves into P2 state. Finally, based on the transient evolution mechanisms, a preliminary state-controlling method regarding the use of a first-peak-leveled applied voltage is proposed, which may shed light on the modification of nonlinear states in some practical DBD application scenarios.
关键词： Dielectric barrier discharge (DBD),nonlinear states,mode transition,transient evolution,state-controlling method
更新于2025-09-04 15:30:14
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A deconvolution technique to correct deep images of galaxies from instrumental scattered light
摘要： Deep imaging of the di?use light that is emitted by stellar ?ne structures and outer halos around galaxies is often now used to probe their past mass assembly. Because the extended halos survive longer than the relatively fragile tidal features, they trace more ancient mergers. We use images that reach surface brightness limits as low as 28.5?29 mag arcsec?2 (g-band) to obtain light and color pro?les up to 5–10 e?ective radii of a sample of nearby early-type galaxies. These were acquired with MegaCam as part of the CFHT MATLAS large programme. These pro?les may be compared to those produced using simulations of galaxy formation and evolution, once corrected for instrumental e?ects. Indeed they can be heavily contaminated by the scattered light caused by internal re?ections within the instrument. In particular, the nucleus of galaxies generates arti?cial ?ux in the outer halo, which has to be precisely subtracted. We present a deconvolution technique to remove the arti?cial halos that makes use of very large kernels. The technique, which is based on PyOperators, is more time e?cient than the model-convolution methods that are also used for that purpose. This is especially the case for galaxies with complex structures that are hard to model. Having a good knowledge of the point spread function (PSF), including its outer wings, is critical for the method. A database of MegaCam PSF models corresponding to di?erent seeing conditions and bands was generated directly from the deep images. We show that the di?erence in the PSFs in di?erent bands causes arti?cial changes in the color pro?les, in particular a reddening of the outskirts of galaxies having a bright nucleus. The method is validated with a set of simulated images and applied to three representative test cases: NGC 3599, NGC 3489, and NGC 4274, which exhibits a prominent ghost halo for two of them. This method successfully removes this.
关键词： galaxies: photometry,techniques: photometric,galaxies: elliptical and lenticular, cD,galaxies: evolution,galaxies: stellar content,techniques: image processing
更新于2025-09-04 15:30:14
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Enhanced Photoelectrocatalytic H <sub/>2</sub> Evolution over Two-Dimensional MoS <sub/>2</sub> Nanosheets Loaded on Cu-Doped CdS Nanorods
摘要： Transition-metal ion doping and efficient decoration by using a co-catalyst have been proven to effectively inhibit the recombination of photogenerated electron-hole pairs and broaden the visible-light response region. Here, we have constructed MoS2 nanosheets decorated on a copper-doped CdS nanorod composite as a noble-metal-free photoelectrocatalyst. This kind of composite material was constructed through a simple solvothermal method. The morphology, structure, chemical states, photoelectrochemical properties, and other properties were tested by using a diverse range of analytical techniques. Owing to the Cu2 + doping and the excellent electron-capturing ability of MoS2, 5 % MoS2/Cu(cid:0) CdS (with 7 % Cu2 + doping in CdS) exhibits excellent hydrogen evolution reaction with a rate of 10.18 mmol h(cid:0) 1 g(cid:0) 1, which is about 48 times higher than that of pure CdS. A significant increase in the photoelectrochemical performance of the composite catalytic material benefits from the synergistic effect between CdS and MoS2 and fast interfacial charge transfer, owing to the Cu2 + doping. These findings provide a new thought for further research of the ion doping in photoelectrocatalytic field.
关键词： CdS,hydrogen evolution reaction,photoelectrochemical performance,MoS2,Cu2 + doping
更新于2025-09-04 15:30:14
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Oxygen vacancy‐rich anatase TiO2 hollow spheres via liquid nitrogen quenching process for enhanced photocatalytic hydrogen evolution
摘要： Development of novel methods to obtain highly active catalysts for photocatalytic hydrogen evolution is desired. This work reports a facile preannealing-quenching strategy to synthesize oxygen vacancy-rich anatase TiO2 hollow spheres. TiO2 hollow spheres are first synthesized via a versatile kinetics-controlled coating method and then subjected to high temperature preannealing followed by rapid quenching in liquid-nitrogen (-196 oC). The as-quenched samples appear light grey suggesting the presence of abundant surface oxygen vacancies, which are subsequently confirmed by the comprehensive analyses of XRD, XPS and EPR spectra. The oxygen vacancies induced by quenching process are proved to have promoted the light adsorption and inhibited the recombination of photo-induced charges for TiO2 hollow spheres, which obviously improve the photocatalytic performance of those samples. The results showed that the TiO2 hollow spheres quenched at 500 oC exhibited a robust stability and the most excellent photocatalytic performance for hydrogen evolution (413.5 μmol·h-1) over other quenched samples and it displayed 1.51 times higher performance than that of samples normally cooled at 500 oC (273.7 μmol · h-1). Herein, this liquid-nitrogen quenching strategy presented here provides an effective route for the synthesis of high-performance TiO2 for water splitting and have a promising prospect in the other application.
关键词： quenching,hollow spheres,photocatalytic hydrogen evolution,oxygen defects,titanium dioxide
更新于2025-09-04 15:30:14
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Enhancement of visible‐light photocatalytic hydrogen production by CeCO3OH in g‐C3N4/CeO2 system
摘要： Promoting the separation of photo-generated carriers is significantly important to improve the efficiency of photocatalytic hydrogen production. Therefore, we prepared g-C3N4/CeCO3OH/CeO2 (CeCeCN) ternary nanocomposite via an easy synthetic way using g-C3N4 and CeO2 as reactants. A CeCO3OH layer was formed and resulted in the novel ternary photocatalyst. The CeCeCN composite shows superior photocatalytic (PC) H2 generation performance in sunlight excitation. The H2 evolution rate is about 764 μmol h-1 g-1, which is over 11 times larger than those of g-C3N4 and CeO2. Compared with g-C3N4 and CeO2, CeCeCN further shows a larger photo-response current density and a lower charge-transfer resistance. The remarkably increased photocatalytic property of CeCeCN is because of the efficient charge migration induced by the formed heterojunction. Our findings demonstrate that building multi-heterostructures can liberate more excited electrons for efficient hydrogen production under sunlight.
关键词： heterojunction,CeCO3OH,g-C3N4/CeCO3OH/CeO2,photocatalytic hydrogen evolution,ternary
更新于2025-09-04 15:30:14
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A Metal‐Organic‐Framework‐Derived g‐C3N4/α‐Fe2O3 Hybrid for Enhanced Visible‐Light‐Driven Photocatalytic
摘要： As one of the most efficient systems for photocatalytic hydrogen evolution, the Z-scheme system consisting of different semiconductors with a reversible donor-acceptor pair has attracted great attention. Considering for the nontoxicity and low cost of photocatalysts, a series of g-C3N4/α-Fe2O3 hybrids were rationally constructed based on the Z-scheme mechanism for the first time using a metal-organic framework template approach that can fine-tune the compositions and properties of the hybrids. An optimized hybrid, g-C3N4/α-Fe2O3-2, exhibited prominent photocatalytic water splitting performance with a visible light response. Under irradiation of visible light (λ > 420 nm), the hybrid shows a high durability and superior hydrogen production rate of 2066.2 μmol g-1 h-1 from water splitting, which is approximately three times greater than that of bulk g-C3N4 because of the effective separation of photo-excited charge carriers by two narrow bandgap semiconductors tightly coupled with the Z-scheme structural feature.
关键词： Z-scheme system,hydrogen evolution,g-C3N4/α-Fe2O3 hybrid,metal-organic frameworks
更新于2025-09-04 15:30:14
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Laccase activity measurement by FTIR spectral fingerprinting
摘要： Laccases (EC 1.10.3.2) are enzymes known for their ability to catalyze the oxidation of phenolic compounds using molecular oxygen as the final electron acceptor. Laccase activity is commonly determined by monitoring spectrophotometric changes (absorbance) of the product or substrate during the enzymatic reaction. Fourier Transform Infrared Spectroscopy (FTIR) is a fast and versatile technique where spectral evolution profiling, i.e. assessment of the spectral changes of both substrate and products during enzymatic conversion in real time, can be used to assess enzymatic activity when combined with multivariate data analysis. We employed FTIR to monitor enzymatic oxidation of monolignols (sinapyl, coniferyl and p-coumaryl alcohol), sinapic acid, and sinapic aldehyde by four different laccases: three fungal laccases from Trametes versicolor, Trametes villosa and Ganoderma lucidum, respectively, and one bacterial laccase from Meiothermus ruber. By coupling the FTIR measurements with Parallel Factor Analysis (PARAFAC) we established a quantitative assay for assessing laccase activity. By combining PARAFAC modelling with Principal Component Analysis we show the usefulness of this technology as a multivariate tool able to compare and distinguish different laccase reaction patterns. We also demonstrate how the FTIR approach can be used to create a reference system for laccase activity comparison based on a relatively low number of measurements. Such a reference system has potential to function as a high-throughput method for comparing reaction pattern similarities and differences between laccases and hereby identify new and interesting enzyme candidates in large sampling pools.
关键词： FTIR,PARAFAC,enzyme activity assay,spectral evolution profiles,Laccase,high-throughput
更新于2025-09-04 15:30:14
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Rapid fabrication of KTa0.75Nb0.25/g-C3N4 composite via microwave heating for efficient photocatalytic H2 evolution
摘要： A novel KTa0.75Nb0.25O3 (KTN)/g-C3N4 composite photocatalyst was fabricated through microwave heating for realizing the e?cient photocatalytic H2 evolution. The energy-e?cient preparation method allowed g-C3N4 to be formed in-situ on KTN surface in thirty ?ve minutes. The binary constitution of the KTN/g-C3N4 composite was veri?ed by X-ray di?raction (XRD) and X-ray photoelectron spectroscopy (XPS) experiments. UV–visible di?use re?ection spectroscopy (DRS) experiments suggested that the photoabsorption performance was increased after the introduction of KTN. N2-adsorption analysis indicated that the addition of KTN slightly increased the surface area of g-C3N4. Photoluminescence (PL) spectroscopy, electrochemical impedance spectroscopy (EIS) and transient photocurrent response (PC) analyses con?rmed that the KTN/g-C3N4 composite displayed longer lifetime of photoexcited charge carriers than g-C3N4, owing to the suitable band potentials and the close contact of KTN and g-C3N4. This property was believed to the key characteristic of the composite, which led to its excellent photocatalytic performance. Under simulated sunlight irradiation, the optimal KTN/g-C3N4 catalyst presented a photocatalytic H2-generation rate of 1673 μmol·g?1·h?1, 2.5 and 2.4 times higher than that of KTN and pure g-C3N4, respectively. Under visible light irradiation, the value was determined to be 86.2 μmol·g?1·h?1, which achieved 9.3 times that of g-C3N4.
关键词： Microwave heating method,KTa0.75Nb0.25O3,Photocatalytic H2 evolution,g-C3N4
更新于2025-09-04 15:30:14