- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
Morphology-selective preparation and formation mechanism of few-layer graphene on Cu substrate by liquid-phase pulsed laser ablation
摘要： This paper presented a morphology-selective preparation and formation mechanism of few-layer graphene (FLG) on a Cu substrate by pulsed laser ablation in liquid. It is a simple and controllable route to grow FLG directly on the surface of a copper foil at ambient temperature and normal pressure, which does not need other precursor materials. FLG with 3–10 layers of thickness and continuous hundreds of micrometers in lateral size is obtained. The morphology and structure of FLG were investigated by using a Raman spectrometer, scanning electron microscope, high-resolution transmission electron microscope, and atomic force microscope. The formation mechanism of FLG and the role of the plasma-produced carbon species are put forward based on the interaction between the laser, material, and substrate. Our finding, the direct deposition of FLG on the Cu substrate by pulsed laser ablation in liquid, will open a door to apply this green route to the production of FLG with controlled morphology.
关键词： formation mechanism,Cu substrate,morphology-selective preparation,few-layer graphene,liquid-phase pulsed laser ablation
更新于2025-09-16 10:30:52
-
Tin-(IV) dopant-controlled synthesis of Yb3+/Er3+:NaGdF4 nanocrystals: Morphology transformation and intensified upconversion performance
摘要： Hexagonal Yb3t/Er3t:NaGdF4 nanocrystals codoped with Sn4t ions were produced via an adjustive solvothermal approach. Simultaneous morphology regulation and intensified upconversion (UC) luminescence of Yb3t/Er3t:NaGdF4 nanocrystals were achieved through Sn4t ions doping. Upon introducing Sn4t ions into the NaGdF4 host, a part of the nanocrystals were converted to nanocubes. By optimizing the Sn4t ions doping content to 40 mol%, UC luminescence intensity of the green and red emissions were intensified by 21 and 31 times, respectively. Moreover, the possible mechanisms for morphology transformation and UC luminescence enhancement of Sn4t-doped Yb3t/Er3t:NaGdF4 nanocrystals were discussed elaborately. Additionally, in contrast to the sample fabricated by co-precipitation method, the result indicated that the UC luminescence intensity with 40 mol% Sn4t ions doping was about 2.5 times higher than the former one. This research could be helpful for designing high-performance UC materials and fulfilling their practical applications.
关键词： Sn4t,Upconversion materials,NaGdF4,Upconversion performance,Morphology
更新于2025-09-16 10:30:52
-
The Influence of Immerse Times PbI2 in CH3NH3I Solutions on Microstructure and Perovskite Solar Cell Performance
摘要： Perovskite solar cells have achieved high power conversion efficiency (PCE) in a short time. In this study, perovskite film (CH3NH3PbI3) was made by dip coating method varying immerse time 1, 2, 3, and 4 minutes to determine its effect on microstructure and perovskite solar cells performance. The samples were characterized by means of XRD, SEM, UV-Vis. Samples that immerse 1 minute showed the best results in terms of morphology, optical properties, and efficiency. The film has the best particle size distribution with an energy gap of 3.2 eV and has an efficiency of 0.91%.
关键词： ETM,perovskite,morphology,PCE,dip coatin
更新于2025-09-16 10:30:52
-
[IEEE 2019 IEEE International Conference on Manipulation, Manufacturing and Measurement on the Nanoscale (3M-NANO) - Zhenjiang, China (2019.8.4-2019.8.8)] 2019 IEEE International Conference on Manipulation, Manufacturing and Measurement on the Nanoscale (3M-NANO) - The Study on Surface Integrity on Laser-assisted Turning of SiCp/2024Al
摘要： An experimental study was conducted on laser-assisted turning (LAT) of SiCp/2024Al in order to investigate the effects of input variables of LAT and conventional turning (CT) on machining performance of SiCp/2024Al. An experimental study was conducted on LAT of SiCp/2024Al in order to investigate the effects of input variables of LAT and CT on machining performance of SiCp/2024Al. The process benefits of laser processing variables were analyzed by comparing the surface roughness, surface microstructure and residual stress. The variables in LAT are as follows: the cutting speed is 30 to 60 m / min, the feed rate is 0.01 to 0.1 mm/rev, and the laser power is between 0 W and 50 W. The experimental results show that under the same cutting parameters, the LAT outperforms the CT method by reducing the surface roughness value by up to 81.73%. Unlike in CT, LAT produces more residual compressive stress. Micro-structure analysis shows that there are no microcracks on the surface of the workpiece machined by LAT.
关键词： laser-assisted micro-turning,microscopic morphology,SiCp/2024Al,residual stress,surface roughness
更新于2025-09-16 10:30:52
-
[IEEE 2019 IEEE International Conference on Manipulation, Manufacturing and Measurement on the Nanoscale (3M-NANO) - Zhenjiang, China (2019.8.4-2019.8.8)] 2019 IEEE International Conference on Manipulation, Manufacturing and Measurement on the Nanoscale (3M-NANO) - Study on Laser-assisted Machining of Aluminum-based Silicon Carbide
摘要： In order to explore the feasibility of laser-assisted machining (LAM) in the field of metal matrix composites (MMCs), an orthogonal precision micro-cutting experiment of 45% volume fraction aluminum-based silicon carbide (SiCp/Al) was carried out, and the experimental results were analyzed and discussed. The experimental results show that laser-assisted processing can improve the processing characteristics of SiCp/Al materials. Under the appropriate laser power, the laser assisted processing technology can effectively improve the surface roughness of the workpiece to be processed, obtaining a high-quality surface finish, and increase the tool wear resistance to a certain extent at the same time. Laser assisted machining technology can be applied to the processing of metal matrix composites.
关键词： surface morphology,laser-assisted,SiCp/Al,tool wear,surface roughness
更新于2025-09-16 10:30:52
-
Simple fabrication of perovskite solar cells with enhanced efficiency, stability, and flexibility under ambient air
摘要： In order to increase the applicability and commercial potential of perovskite solar cells, simple fabrication of high-photovoltaic-performance flexible perovskite solar cells with excellent moisture stabilities without the use of a glove-box and an antisolvent is required. In this paper, we present a simple fabrication strategy involving introduction of 4-tert-butylpyridine into CH3NH3PbI3 and significantly enhancing 4-tert-butylpyridine morphology-modifying effect via a reduction-active flexible poly (3,4-ethylenedioxythiophene):poly (styrenesulfonate) interlayer. Owing to the specific oxidation facilitation by the poly (3,4-ethylenedioxythiophene):poly (styrenesulfonate) polymer, a perovskite film with large (~1 μm) and quasi-all-in-one-structured grains can be obtained, which significantly enhance the efficiency and the stability of the perovskite solar cells. Furthermore, the high-efficiency flexible perovskite solar cells fabricated by the simple strategy exhibit excellent moisture resistances owing to the stronger coordination and the outside-covering effect of the hydrophobic 4-tert-butylpyridine. The fabrication can be carried out under ambient air (without glovebox, relative humidity > 40%), which paves the way for wearable device application and commercialization.
关键词： Flexible perovskite solar cells,Ambient-air fabrication,Morphology-modifying,Moisture stability,4-tert-butylpyridine
更新于2025-09-16 10:30:52
-
[Institution of Engineering and Technology 20th Italian National Conference on Photonic Technologies (Fotonica 2018) - Lecce, Italy (23-25 May 2018)] 20th Italian National Conference on Photonic Technologies (Fotonica 2018) - Polarization digital holography for birefringence characterization of sperm cells
摘要： Birefringence in sperm heads depends on a very compact and organized structural normality. Additionally, when the acrosome reaction happens, due to a reorganization of the proteins, the birefringence occurs only in the post-acrosomal region. Thus, the polarization state of the semen is an interesting method to characterize their healthy state and to select reacted sperm cells. In this paper, a characterization of the birefringence pattern of sperm head by polarized digital holography microscopy is presented as a label free technique.
关键词： Digital holography,Sperm selection,Digital morphology,Sperm texture,Birefringence
更新于2025-09-16 10:30:52
-
Numerical simulation of selective laser melting temperature conduction behavior of H13 steel in different models
摘要： With considering the latent heat of melting and the temperature-dependent thermo-physical properties, a Gauss body heat source is employed to analyze the temperature field and the morphology of molten pool with a single-track and multi-track scan strategy in Substrate-Powder (SP) model, Full-Powder (FP) model and Partial-Solid model (PS), respectively. It is shown that the maximum temperature (Tmax) and maximum cooling rate (vcmax) of single-track increase with preheating temperature, while the maximum heating rate (vhmax) presenting an opposite trend. The preheating temperature has the greatest influence on the length and depth of the molten pool of SP model and the width of FP model. For the reason of heat accumulation, the Tmax of each track increases with the decrease of solid volume in the model and increases with the number of scan tracks in a multi-track scan strategy. Due to prominent thermal conductivity of SP model, heat accumulation of multi-track scanning has the smallest effect on the size of pool, but it drives the molten pool length of PS model and FP model increasing seriously. The verification experiment of SP model was in good agreement with the simulation results, proved that numerical simulation is capable of predicting the temperature field and molten pool morphology during the SLM process.
关键词： numerical simulation,H13 steel,temperature field,molten pool morphology,selective laser melting
更新于2025-09-16 10:30:52
-
Influence of surface tension on the molten pool morphology in laser melting
摘要： The surface tension plays an important role in the distribution and evolution of molten pool morphology during laser melting. In this paper, based on the theory of Smoothed Particles Hydrodynamics (SPH), a mathematical model of surface tension on the molten pool morphology is established with the temperature change of molten pool being taken into account. The longitudinal morphology of molten pool and its formation process are simulated by using the SPH method under certain processing parameters, and the distributions of length and depth of molten pool are thoroughly analyzed at various processing parameters. The result shows that the longitudinal morphology of molten pool varying along the longitudinal section of solidified track presents a curve due to the influence of surface tension. A strong influence of Marangoni force on the flow of liquid metal and transformation of heat is also found. Moreover, the longitudinal morphology of a molten pool looks like that of a wave in the simulation; the deformation distributions of the longitudinal morphology of molten pool will increase with increasing laser power or decreasing scanning speed. The longitudinal morphologies of solidified molten pool are observed in the current experiments, and the experimental results are found to be agreed well with the calculated ones.
关键词： Processing parameters,Laser melting,Smoothed particles hydrodynamics (SPH),Molten pool morphology,Surface tension
更新于2025-09-16 10:30:52
-
Ternary small molecules organic photovoltaics exhibiting 12.84% efficiency
摘要： Small molecules organic photovoltaics (SMPVs) were prepared with DR3TSBDT as donor, narrow band gap material Y6 and broad band gap material PC71BM as acceptor. The Y6 based binary SMPVs exhibits a power conversion efficiency (PCE) of 10.53%, with short-circuit density (JSC) of 21.67 mA cm-2, open circuit voltage (VOC) of 0.879 V and fill factor (FF) of 55.21%. A 12.84% PCE is achieved from the optimized ternary SMPVs with 40 wt% PC71BM in acceptors, which is attributed to the enhanced JSC of 22.19 mA cm-2 and FF of 67.27% resulting from the well-optimized phase separation with PC71BM as morphology regulator. Hollow spherical structure of PC71BM with high electron mobility may connect Y6 molecules to form the more continuous electron transport channels in ternary active layers. Meanwhile, DR3TSBDT molecular arrangement can be markedly adjusted by incorporating PC71BM to form 3D texture structure. The well-optimized phase separation degree and molecular arrangement in ternary active layers can well support the enhanced FFs of ternary SMPVs compared with that of binary SMPVs. Over 21% PCE improvement is achieved by employing ternary strategy with 40 wt% PC71BM in acceptors, the 12.84% PCE should be among the highest values of SMPVs.
关键词： Small molecules organic photovoltaics,Ternary strategy,Morphology regulator,Power conversion efficiency
更新于2025-09-16 10:30:52