- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
Microstructure and properties of CeO2-doped CoCrFeMnNi high entropy alloy fabricated by laser metal deposition
摘要： Rare earth elements are usually regarded as e?cient additives for property enhancement of many types of alloys. In the present study, the CoCrFeMnNi high entropy alloy (HEA) was doped with CeO2, and such composites were for the ?rst time obtained by the laser metal deposition (LMD) process. The microstructure, phase compositions, microhardness and crystallographic texture of the HEA/CeO2 composites were investigated. It was demonstrated that CoCrFeMnNi HEA/CeO2 samples were successfully obtained by the LMD process. Meanwhile, small irregular shape oxides rich in Mn and Cr were observed in the HEA/ CeO2 composite. Rare earth element Ce was found to be evenly distributed throughout the sample. Heterogeneous dendritic microstructure with a long columnar grains oriented along the build direction was observed. The measured average microhardness is 181.72 ± 9.72 HV0.1.
关键词： Composite,CeO2,High entropy alloy,Laser metal deposition,Additive manufacturing,CoCrFeMnNi
更新于2025-09-23 15:21:01
-
Controlled synthesis of AgNPs@ZIF-8 composite: Efficient heterogeneous photocatalyst for degradation of methylene blue and congo red
摘要： Photocatalytic degradation of organic dyes using novel metal based composite materials is one of the most intriguing and sustainable ways to reduce water pollution. Herein, facile synthesis of AgNPs@ZIF-8 via in situ generation of AgNPs and ZIF-8 (Zeolitic Imidazolate Framework) was demonstrated, and composites with different Ag contents (abbreviated as SZ, SZ1, SZ2 SZ3) were well characterized by powder X-ray diffraction (PXRD) pattern, X-ray photoelectron spectroscopy (XPS) and Fourier transform infra-red (FT-IR) spectroscopy. Encapsulation/decoration of AgNPs (particle size: 96 nm in SZ and 17.32 ± 2.35 nm in SZ1 to SZ3) in ZIF-8 matrix has been ensured by TEM and EDX analysis. Brunauer-Emmett-Teller (BET) adsorption-desorption studies indicate that the surface area of SZ (982 m2 g?1) is less than those of SZ1 to SZ3 (due to the encapsulation of large amount of Ag nanoparticles in SZ). The synthesized composites are thermally stable up to 400 °C in air and nitrogen atmosphere. AgNPs@ZIF-8 exhibited excellent photocatalytic efficiency to degrade organic dyes compared to ZIF-8 due to its large surface area, highly porous and unique synergistic properties. SZ2 degrades off 97.25 % methylene blue (MB) and 100 % congo red (CR) at pH ≥ 7. Further, degraded fragments were analysed by GC–MS and plausible degradation mechanism was discussed.
关键词： Silver nanoparticles,Organic pollutants,Photocatalyst,Heterogeneous catalysis,Composite materials
更新于2025-09-23 15:21:01
-
Effect of laser parameters on microstructure and phase evolution of Ti-Si-C composites prepared by selective laser melting
摘要： In this paper, blended Ti/SiC powder was processed by selective laser melting (SLM) method to prepare a novel kind of Ti-Si-C composite. Microstructure, elements distribution and phase evolution of Ti-Si-C composites fabricated by SLM were studied. SEM, EDS, TEM and XRD were performed to evaluate the microstructure and phase evolution during the SLM process. The results showed that processing parameters significantly affected the microstructure and element distribution of the samples. It was found that higher laser energy density could promote the densification process and hence suppress balling phenomenon of Ti-rich phases. At the micro-level, the microstructure could be classified into the dense area and the porous area, which was closely related to the redistribution of elements. The phases obtained by the SLM process were composed by TiCx, TiSi2, Ti5Si3, and Ti5Si4, which appeared in different microstructures. The results indicated that composites with different phases and microstructure could be obtained by merely modifying laser processing parameters, which could give experimental guidance for the fabricating of gradient Ti-Si-C composites by selective laser melting without additional apparatus on powder feeding.
关键词： Microstructure evolution,Phase evolution,Ti-Si-C composite,Selective laser melting
更新于2025-09-23 15:21:01
-
1D/2D WO3 nanostructure coupled with nanoparticulate CuO cocatalyst for enhancing solar-driven CO2 photoreduction: The impact of the crystal facet
摘要： Photocatalytic reduction of CO2 into solar fuels is regarded as one of the most promising approaches to address the issues of global warming and the energy crisis. The promotion of spatial charge separation and transfer through crystal facet engineering could be conducive to improved photocatalytic activity. In this study, one-dimensional (1D) WO3 nanowires with a {110} dominant facet (WO3-110) and two-dimensional (2D) WO3 nanosheets with a {001} dominant facet (WO3-001) coupled with CuO nanoparticles are fabricated by a facile method and used for CO2 photoreduction. Its composition and structural characterizations suggest that the WO3-CuO hybrid features good contact between the WO3 and CuO nanostructures. Under light irradiation, the WO3 and WO3-CuO nanostructures are able to photoreduce CO2 into CH4. Notably, the prepared WO3-CuO nanohybrids with different exposed facets show improved CO2 reduction capability compared to pure WO3 and CuO. The heterojunction interface between the WO3 photocatalyst and the CuO cocatalyst through p-n contact can facilitate electron-hole pair separation and accordingly results in enhanced photocatalytic performance. With the assistance of the CuO cocatalyst, the {110} facet WO3-CuO hybrid displays superior photoreduction capability compared to the {001} facet WO3-CuO, which is attributed to the difference in the crystal facets in the heterostructure. The {110} facet WO3 nanowires have a more negative conduction band edge, contributing to the higher reduction capacity of this sample. On the other hand, it is shown that faster charge carrier transfer efficiency would enable more photoinduced electrons to participate in CO2 photoreduction, especially with the involvement of the nanoparticulate CuO cocatalyst. This work provides guidance for designing a hetero-photocatalyst-cocatalyst system through crystal facet engineering.
关键词： WO3-CuO composite,CO2 Photoreduction,1D/2D WO3 nanostructures,heterojunction,crystal facet impact
更新于2025-09-23 15:21:01
-
Compact single-layer bandwidth-enhanced balanced bandpass filter using half-mode substrate-integrated waveguide
摘要： One particular challenge in biomedical named entity recognition (NER) and normalization is the identification and resolution of composite named entities, where a single span refers to more than one concept (e.g., BRCA1/2). Previous NER and normalization studies have either ignored composite mentions, used simple ad hoc rules, or only handled coordination ellipsis, making a robust approach for handling multitype composite mentions greatly needed. To this end, we propose a hybrid method integrating a machine-learning model with a pattern identification strategy to identify the individual components of each composite mention. Our method, which we have named SimConcept, is the first to systematically handle many types of composite mentions. The technique achieves high performance in identifying and resolving composite mentions for three key biological entities: genes (90.42% in F-measure), diseases (86.47% in F-measure), and chemicals (86.05% in F-measure). Furthermore, our results show that using our SimConcept method can subsequently improve the performance of gene and disease concept recognition and normalization. SimConcept is available for download at: http://www.ncbi.nlm.nih.gov/CBBresearch/Lu/Demo/SimConcept/
关键词： bioNLP,text mining,composite mentions,named entity recognition,coordination ellipsis
更新于2025-09-23 15:21:01
-
[IEEE 2019 IEEE 4th Optoelectronics Global Conference (OGC) - Shenzhen, China (2019.9.3-2019.9.6)] 2019 IEEE 4th Optoelectronics Global Conference (OGC) - A Fast Acquisition Strategy of Laser Communication on Airship Platform by Small Divergence Angle Composite Scanning
摘要： In this paper, we designed and optimized the ship-to-airship capture scheme of laser communication system according to the characteristics of airship platform. A composite scanning strategy was proposed to solve the problem of the long capture time under the condition of small divergence angle and far distance. The working principle of this composite scanning strategy and the influencing factors in the capture process were analyzed emphatically, meanwhile, LABVIEW was used to simulate the process. It is proved that the capture strategy saved a lot of capture time of dynamic laser communication between the airship and the ship. The simulation results show that the acquisition time is better than Existing modes.
关键词： communication,laser,platform,composite scanning,airship,small divergence angle
更新于2025-09-23 15:21:01
-
Continuous-wave dual-wavelength operation of the in-band diode-pumped Nd:GdVO4/Nd:YVO4 composite laser with controllable spectral power ratio
摘要： Controllable continuous-wave dual-wavelength laser operation of a Nd:GdVO4/Nd:YVO4 composite crystal at 1063 and 1064 nm was demonstrated using in-band diode pumping around 912 nm. The spectral power ratio of the two laser wavelengths could be adjusted simply by controlling the pump wavelength of the laser diode via temperature. The laser produced the maximum total output power of 4.48 W. The maximum slope and optical-to-optical efficiency with respect to the absorbed pump power were 43.8% and 38.8%, respectively.
关键词： in-band diode pumping,Nd:GdVO4/Nd:YVO4 composite crystal,dual-wavelength laser,spectral power ratio,continuous-wave operation
更新于2025-09-23 15:21:01
-
Enhanced Photosensitization by Carbon Dots Co-adsorbing with Dye on p-Type Semiconductor (Nickel Oxide) Solar Cells
摘要： In this work, the effect of carbon dots (C-dots) on the performance of NiO-based dye-sensitized solar cells (DSSCs) was explored. NiO nanoparticles (NPs) with a rectangular shape (average size: 11.4 x 16.5 nm) were mixed with C-dots, which were synthesized from citric acid (CA) and ethylenediamine (EDA). A photocathode consisting of a composite of C-dots with NiO NPs (NiO@C-dots) was then used to measure the photovoltaic performance of a DSSC. A power conversion efficiency (PCE) of 9.85 % (430 nm LED@50 mWcm-2) was achieved by a DSSC fabricated via the adsorption of N719 sensitizer with a C-dot content of 12.5 wt% at a 1.5:1 EDA:CA molar ratio. This PCE value was far larger than the PCE value (2.44 or 0.152 %) obtained for a NiO DSSC prepared without the addition of C-dots or N719, respectively, indicating the synergetic effect by the co-adsorption of C-dots and N719. This synergetically higher PCE of the NiO@C-dots-based DSSC was due to the larger amount of sensitizer adsorbed onto the composites with a larger specific surface area and the faster charge transfer in the NiO@C-dots working electrode. In addition, the C-dots bound onto the NiO NPs shorten the bandgap of the NiO NPs due to energy transfer and give rise to faster charge separation in the electrode. The most important fact is that C-dots are the main sensitizer and N719 tightly adsorbed on C-dots and NiO behaves as an accelerator of a positive electron transfer and a restrainer of the electron-hole recombination. These results reveal that C-dots are a remarkable enhancer for NiO NPs in DSSCs, and that NiO@C-dots are the promising photovoltaic-electrode materials for DSSCs.
关键词： dye-sensitized solar cell,power conversion efficiency,nickel oxide@carbon dots composite,Nickel oxide,carbon dot
更新于2025-09-23 15:21:01
-
Strategies to Achieve High Performance Piezoelectric Nanogenerators
摘要： Piezoelectric nanogenerators have attracted much attention in the past decade. In this study, the development of piezoelectric nanogenerators and their progress toward high power generation is discussed. The characteristics and application range of numerous types of piezoelectric nanogenerators are also considered. In addition, several strategies that may improve the performance of piezoelectric nanogenerators are summarized. Here, we compare the open circuit voltages and short circuit currents of various piezoelectric nanogenerators under different factors, and the current problems of piezoelectric nanogenerators are also discussed. Finally, the future prospects and directions of piezoelectric nanogenerators are predicted. Future studies should be focused on the production of high-performance materials, the establishment of working principle and simulation model, the integration of nanogenerator, and the design of the energy harvesting circuit. Hence, it is emergency to search for functional materials with high piezoelectricity and further improve the electromechanical properties of existing piezoelectric materials. Moreover, further research is needed to increase the stability and flexibility of composite materials, to develop wearable and embedded flexible functional devices based on the biocompatibility of inorganic nanoparticles, and to supply power for microelectronic systems.
关键词： BaTiO3,Piezoelectric nanogenerators,Composite thin film materials,PVDF,Chemical doping,Nanostructure
更新于2025-09-23 15:21:01
-
Compact D-CRLH resonator for low-pass filter with wide rejection band, high roll-off, and transmission zeros
摘要： A compact low-pass filter (LPF) with wide rejection band based on T-type circuit of an enhanced dual composite right-/left-handed (D-CRLH) resonator is presented in this paper. The resonator has only one cell with series and parallel tank circuit. The parallel LC tank circuit has been realized by an interdigital capacitor and one shorted finger, whereas its series LC tank circuit is realized by an air gap capacitance and a short circuit stub. The filter has wide rejection band bandwidth with three transmission zeros (TZs). The filter bandwidth and TZs frequencies are controlled by the D-CRLH element values. The results of the proposed filter demonstrate minimum insertion loss in passband, high roll-off rate, and good figure of merit. The measured results are in good agreement with the simulated results. The detailed filter design is discussed in terms of circuit modeling, dispersion analysis, and full-wave simulation. Finally, the filter size is compact (0.10 λg) at cut-off frequency.
关键词： roll-off,transmission zero,low-pass filter,Dual composite right-/left-handed (D-CRLH)
更新于2025-09-23 15:21:01