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Laser polishing of additively manufactured Ti-6Al-4V: Microstructure evolution and material properties
摘要： Laser polishing of metals consists of irradiating the part’s surface with a laser beam, thus generating a molten layer that is redistributed and resolidified to create a surface with reduced roughness. However, the process is also characterized by an instantaneous formation of heat-affected zones with consequent microstructural changes that influence the mechanical properties. In order to understand the microstructural evolution during laser polishing of Ti-6Al-4V laser-based powder bed fusion samples, a thermal model is applied in the current study to predict the dimensions of the melted zones and the heat-affected areas. Furthermore, the results obtained through simulations are discussed and compared to the experimental data, thereby establishing the validity of the process models. Finally, the experimental studies also include the evaluation of material hardness and residual stresses after laser polishing.
关键词： laser polishing,thermal model,material properties,additive manufacturing,microstructure evolution
更新于2025-09-23 15:21:01
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Densification behavior, microstructure evolution, and tensile properties of selective laser melting additive manufactured TiB <sub/>2</sub> /AlSi10Mg composite
摘要： The fabrication of TiB2/AlSi10Mg composites by selective laser melting (SLM) additive manufacturing has been conducted. The influence of laser processing parameters on the densification behavior, microstructure evolution, and tensile properties of the SLM-processed composites is addressed. With the increase in laser volume energy density, the densification rate increased and reached 99% at a laser speed of 1000 mm/s. Meanwhile, the TiB2 particles underwent a partial melting behavior with the formation of an irregular pattern in the solidified part and complete melting with the smooth surface of the reinforcing particles as the laser volume energy increased. The cellular-dendritic microstructure and the width of the eutectic phase of the as-fabricated composites were significantly refined due to the high cooling rate and complete melting of the reinforcing particles as the nucleation sites using the laser energy density of 117 J/mm3. Therefore, the micro-hardness, ultimate tensile strength, yielding strength, and elongation of the as-fabricated TiB2/AlSi10Mg composites obtained in this process condition were 131.3 HV0.2, 375 MPa, 260 MPa, and 3.1%, respectively, which were significantly higher than those of the unreinforced AlSi10Mg alloy.
关键词： tensile properties,aluminum-based composite,selective laser melting,microstructure evolution
更新于2025-09-23 15:21:01
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[IEEE 2019 24th Microoptics Conference (MOC) - Toyama, Japan (2019.11.17-2019.11.20)] 2019 24th Microoptics Conference (MOC) - Patterned emission of organic light emitting diodes with laser irradiation
摘要： Self-healing networks aim to detect cells with service degradation, identify the fault cause of their problem, and execute compensation and repair actions. The development of this type of automatic system presents several challenges to be confronted. The first challenge is the scarce number of historically reported faults, which greatly complicates the evaluation of novel self-healing techniques. For this reason, in this paper, a system model to simulate faults in Long-Term Evolution (LTE) networks, along with their most significant key performance indicators, is proposed. Second, the expert knowledge required to build a self-healing system is usually not documented. Therefore, in this paper, a methodology to extract this information from a collection of reported cases is proposed. Finally, following the proposed methodology, an automatic fuzzy-logic-based system for fault identification in LTE networks is designed. Evaluation results show that the fuzzy system provides fault identification with a high success rate.
关键词： Long-Term Evolution (LTE),Diagnosis,fuzzy logic,fault identification,troubleshooting,root cause analysis,self-healing,fault management
更新于2025-09-23 15:21:01
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Maximum Power Point Tracking Technology of Photovoltaic Array under Partial Shading Based On Adaptive Improved Differential Evolution Algorithm
摘要： In the case of partial shading conditions, there will be more than one maximum power point (MPP) in photovoltaic (PV) array. The traditional maximum power point tracking (MPPT) methods are easy to get in the local maximum power point (LMPP) and fail. Based on the standard di?erential evolution (DE) algorithm, the mutation strategy, scaling factor F, and cross factor CR of the algorithm are optimized. Also, the population position variance δ2 is used to prevent falling into LMPP. Finally, the conditions for algorithm termination and restart are set. It is veri?ed by simulation that the method has fast convergence speed, high accuracy, and can adapt well to changes in the external environment. The improved DE algorithm has a great advantage in MPPT.
关键词： photovoltaic array,di?erential evolution algorithm,MPPT,DC-DC converter
更新于2025-09-23 15:21:01
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Temporal and spatial evolution measurement of laser-induced breakdown spectroscopy on hydrogen retention in tantalum
摘要： Temporal and spatial evolution measurement of laser-induced breakdown spectroscopy on hydrogen retention in tantalum. Fuel retention measurement on plasma-facing components (PFCs) is an active field of study in magnetic confinement nuclear fusion devices. Laser-induced breakdown spectroscopy (LIBS) diagnostic method has been well demonstrated to detect the elemental distribution in PFCs. In this work, an upgraded co-axis LIBS system based on the linear fibers bundle collection system has been developed to measure the hydrogen (H) retention on tantalum (Ta) sample under the vacuum condition. The spatial resolution measurement on the different positions of the LIBS plasma can be achieved simultaneously with the various delay time. The temporal and spatial evolution of LIBS plasma and optimize the current collection system of the in situ LIBS in fusion devices.
关键词： tokamak,fuel retention,temporal and spatial evolution,laser-induced breakdown spectroscopy
更新于2025-09-23 15:21:01
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Ternary PtNiCu self-assembled nanocubes for plasmon-enhanced electrocatalytic hydrogen evolution and methanol oxidation reaction in visible light
摘要： The strong interaction among metal components results in the change of the electronic structure (e.g. d-band energy level) of noble metal-based alloy structures which enables the increase of catalytic activity. In this paper, self-assembled ternary PtNiCu and binary PtCu alloy nanocubes are synthesized by a one-pot high-temperature chemical reduction method. The growth mechanism of the alloy is investigated. The alloy is applied to visible light-assisted electrocatalytic hydrogen production and methanol oxidation. The ternary PtNiCu alloy exhibits superior catalytic performance (a minimum over potential of 15 mV at a current density of 10 mA cm-2, a Tafel slope of 24.1 mV/dec, and more excellent mass specific activity under visible light irradiation about 3.3 A mgPt -1), because of its regular morphology, more surface active sites, and more intense interaction between metal elements. Especially the localized surface plasmon resonance effect of Cu largely increases the electron density (photoelectric effect) on Pt under illumination, thereby further improves the photo-assisted hydrogen production and methanol catalytic oxidation performance. The results will promote efficient and accurate electrocatalysis process, paving new way for a brighter further in rational design of ternary plasmonic electrocatalysts and photoelectrocatalysis field.
关键词： Methanol oxidation reaction,Photoelectrocatalysis,Hydrogen evolution reaction,Ternary PtNiCu alloy
更新于2025-09-23 15:21:01
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Self-assembled CdS@BN core-shell photocatalysts for efficient visible-light-driven photocatalytic hydrogen evolution
摘要： CdS@BN NRs core-shell photocatalysts for hydrogen evolution were synthesized by a solvothermal and chemical adsorption method. CdS NRs coated by 5 wt% boron nitride (BN) shell exhibited remarkably visible-light photocatalytic hydrogen evolution activity of up to 30.68 mmol g?1 h?1, nearly 6.79 times higher than that of pure CdS NRs, and the apparent quantum efficiency at 420 nm was 7.5%. Transmission electron microscopy showed the CdS NRs were coated with a thin (~5 nm) BN layer, which together with the hydrogen evolution results proved the photocatalytic ability of CdS NRs was significantly improved. The hydrogen evolution rate of CdS NRs coated by 5 wt% BN remained at 91.4% after four cycles, indicating the photocorrosion of CdS NRs was effectively alleviated. Moreover, the large and close coaxial interfacial contact between the CdS core and the BN shell was beneficial to the separation and transfer of photogenerated electron-hole pairs.
关键词： Core-shell structure,Photocatalytic hydrogen evolution,CdS Nanorods,Boron nitride
更新于2025-09-23 15:21:01
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Determining Plasmonic Hot Electron and Photothermal Effects during H <sub/>2</sub> Evolution with TiN-Pt Nanohybrids
摘要： Hydrogen storage in chemical compounds is a promising strategy to enable lightweight, high density, and safe hydrogen technologies. However, the hydrogen release rate from these chemicals is limited by the intrinsic catalytic activity of metal catalysts, which can be enhanced by using light irradiation. Here nanohybrids including a core of plasmonic TiN and multiple Pt nanocrystal catalytic centers are assembled and show, under resonant conditions at 700 nm, hot electrons driven hydrogen evolution from ammonia borane at an apparent quantum yield of 120%. It is also demonstrated that solar irradiation enhances the activity of TiN-Pt nanohybrids by one order of magnitude through two synergistic mechanisms: the hot electrons and collective-heating contributions. Using the microscopic calculation of the photoinduced temperature around a single nanocrystal, it is revealed that the collective plasmonic heating regime dominates the macroscopic temperature distribution in the system. The presented data show that plasmonic hot electrons and photothermal heating can be used in synergy to trigger hydrogen release from ammonia borane on demand, providing a general strategy for greatly enhancing the activity in the dark of metal catalysts.
关键词： ammonia-borane,plasmonics,photocatalysis,titanium nitride,hydrogen evolution
更新于2025-09-23 15:21:01
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A Scalable Soft-Switching Photovoltaic Inverter with Full-Range ZVS and Galvanic Isolation
摘要： The introduction of heterogeneous wireless mesh technologies provides an opportunity for higher network capacity, wider coverage, and higher quality of service (QoS). Each wireless device utilizes different standards, data formats, protocols, and access technologies. However, the diversity and complexity of such technologies create challenges for traditional control and management systems. This paper proposes a heterogeneous metropolitan area network architecture that combines an IEEE 802.11 wireless mesh network (WMN) with a long-term evolution (LTE) network. In addition, a new heterogeneous routing protocol and a routing algorithm based on reinforcement learning called cognitive heterogeneous routing are proposed to select the appropriate transmission technology based on parameters from each network. The proposed heterogeneous network overcomes the problems of sending packets over long paths, island nodes, and interference in WMNs and increases the overall capacity of the combined network by utilizing unlicensed frequency bands instead of buying more license frequency bands for LTE. The work is validated through extensive simulations that indicate that the proposed heterogeneous WMN outperforms the LTE and Wi-Fi networks when used individually. The simulation results show that the proposed network achieves an increase of up to 200% in throughput compared with Wi-Fi-only networks or LTE-only networks.
关键词： routing protocol,long-term evolution (LTE),reinforcement learning,next-generation network,Heterogeneous networks,wireless mesh network (WMN)
更新于2025-09-23 15:21:01
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Metallic 1T-MoS2 nanosheets and their composite materials: Preparation, properties and emerging applications
摘要： Metallic 1T phase MoS2 nanosheets and their composite materials, with unique structure and unusual properties, have attracted increasing research interest in energy conversion/storage and catalysis in the past few years. In this work, an overview of the recent progress of metallic 1T-MoS2 nanosheets and their composite materials is presented. First, we focused on the controlled synthesis of 1T-MoS2 nanosheets and their composite materials using top-down and bottom-up approaches and their unusual properties while tuning the phase structure. Then, we discussed their promising applications in energy-related areas including hydrogen evolution reaction, supercapacitors, batteries, and photocatalysis. In addition, an in-depth understanding was provided on phase tuning of these advanced materials for improved performance. Finally, the existing challenges and future research in these emerging research areas are also described.
关键词： Batteries,Hydrogen evolution reaction,Metallic 1T-MoS2 nanosheets,Properties,Photocatalysis,Supercapacitors
更新于2025-09-23 15:21:01