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| 2. |
- Li, Mengxiong, et al.
(författare)
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Highly Oriented Graphite Aerogel Fabricated by Confined Liquid-Phase Expansion for Anisotropically Thermally Conductive Epoxy Composites
- 2020
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Ingår i: ACS Applied Materials & Interfaces. - : American Chemical Society (ACS). - 1944-8252 .- 1944-8244. ; 12:24, s. 27476-27484
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Tidskriftsartikel (refereegranskat)abstract
- Graphene-based thermally conductive polymer composites are of great importance for the removal of the excess heat generated by electronic devices. However, due to the orientation of graphene sheets in the polymer matrix, the through-plane thermal conductivity of polymer/graphene composites remains far from satisfactory. We here demonstrate a confined liquid-phase expansion strategy to fabricate highly oriented confined expanded graphite (CEG) aerogels. After being incorporated into epoxy resin (EP), the resulting EP/CEG composites exhibit a high through-plane thermal conductivity (4.14 ± 0.21 W m-1 K-1) at a quite low filler loading of 1.75 wt % (0.91 vol %), nearly 10 times higher than that of neat EP resin and 7.5 times higher than the in-plane thermal conductivity of the composite, indicating that the CEG aerogel has a high through-plane thermal conductivity enhancement efficiency that outperforms those of many graphite/graphene-based fillers. The facile preparation method holds great industrial application potential in fabricating anisotropic thermally conductive polymer composites.
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| 3. |
- Ye, Xiaoling, et al.
(författare)
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Advances in the Field of Two-Dimensional Crystal-Based Photodetectors
- 2023
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Ingår i: Nanomaterials. - : MDPI. - 2079-4991. ; 13:8
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Forskningsöversikt (refereegranskat)abstract
- Two-dimensional (2D) materials have sparked intense interest among the scientific community owing to their extraordinary mechanical, optical, electronic, and thermal properties. In particular, the outstanding electronic and optical properties of 2D materials make them show great application potential in high-performance photodetectors (PDs), which can be applied in many fields such as high-frequency communication, novel biomedical imaging, national security, and so on. Here, the recent research progress of PDs based on 2D materials including graphene, transition metal carbides, transition-metal dichalcogenides, black phosphorus, and hexagonal boron nitride is comprehensively and systematically reviewed. First, the primary detection mechanism of 2D material-based PDs is introduced. Second, the structure and optical properties of 2D materials, as well as their applications in PDs, are heavily discussed. Finally, the opportunities and challenges of 2D material-based PDs are summarized and prospected. This review will provide a reference for the further application of 2D crystal-based PDs.
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| 4. |
- Zhao, Mingyue, et al.
(författare)
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Advances in Two-Dimensional Materials for Optoelectronics Applications
- 2022
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Ingår i: Crystals. - : MDPI. - 2073-4352. ; 12:8
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Forskningsöversikt (refereegranskat)abstract
- The past one and a half decades have witnessed the tremendous progress of two-dimensional (2D) crystals, including graphene, transition-metal dichalcogenides, black phosphorus, MXenes, hexagonal boron nitride, etc., in a variety of fields. The key to their success is their unique structural, electrical, mechanical and optical properties. Herein, this paper gives a comprehensive summary on the recent advances in 2D materials for optoelectronic approaches with the emphasis on the morphology and structure, optical properties, synthesis methods, as well as detailed optoelectronic applications. Additionally, the challenges and perspectives in the current development of 2D materials are also summarized and indicated. Therefore, this review can provide a reference for further explorations and innovations of 2D material-based optoelectronics devices.
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| 5. |
- Xu, Kangjun, et al.
(författare)
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Association between serum vitamin B12 and risk of all-cause mortality in elderly adults : a prospective cohort study
- 2021
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Ingår i: BMC Geriatrics. - : BioMed Central. - 1471-2318 .- 1471-2318. ; 21:1
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND AND PURPOSE: Results from previous studies that linking vitamin B12 to risk of chronic diseases or mortality are inconsistent. We hereby explore the association between serum concentration of vitamin B12 and all-cause mortality risk in elderly adults.METHODS: Participants aged over 65 years in the Chinese Longitudinal Healthy Longevity Survey were included in present prospective cohort study. Serum vitamin B12 was assessed at the 2011-2012 and 2014 wave, respectively. Participants were divided into three groups based on two cut-off points - 10th and 90th percentiles of vitamin B12 concentrations - in the whole population. Cox regression model was used to calculate the hazard ratio (HR) and 95 % confidence intervals (95 % CIs), and restricted cubic spline function was further modelled to investigate their dose-response associations.RESULTS: Among 2,086 participants [mean ± SD: 87.74 ± 11.24 years, 908 (43.53 %) males], 943 (45.21 %) died during an average follow-up of 3.34 (SD: 1.63) years. Comparing with participants with middle concentration of serum vitamin B12, participants with high concentration had an increased risk of all-cause mortality [HR (95 %CIs): 1.30 (1.03-1.64)], whereas participants with low concentration had an insignificantly decreased risk of all-cause mortality (0.96, 0.76-1.20). The positive association between high concentration of serum vitamin B12 and all-cause mortality was also observed among the male and in a series of sensitivity analyses. In the dose-response analysis, a J-shape pattern was observed, but the non-linear association was only significant in males (Pnon-linearity = 0.0351).CONCLUSIONS: High concentration of serum vitamin B12 was associated with an increased risk of all-cause mortality in a J-shaped pattern. The precise mechanisms underlying the association remain to be explored.
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| 6. |
- Chen, Zhang, et al.
(författare)
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Making monolayer graphene photoluminescent by electron-beam-activated fluorination approach
- 2023
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Ingår i: Applied Surface Science. - : Elsevier. - 0169-4332 .- 1873-5584. ; 608
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Tidskriftsartikel (refereegranskat)abstract
- The past one and half decades have witnessed a tremendous development of graphene electronics, and the key to the success of graphene is its exceptional properties. The lacking of an inherent bandgap endows graphene with excellent electrical properties but considerably limits its applications in light-emitting and high-performance graphene-based devices. Herein, an approach for the direct writing of semiconducting and photoluminescent fluorinated graphene (C4F) patterns on monolayer graphene by an optimized electron-beam-activated fluorination technique is reported. A series of characterization approaches, such as atomic force microscopy, X-ray photoelectron spectroscopy and Raman spectroscopy were used to demonstrate the successful preparation of C4F for maskless lithography. Specially, a sharp and strong photoluminescence located at the purple light range of ∼380 nm was observed in C4F, demonstrating a desirable semiconducting nature, and the bandgap was further confirmed by follow-up electrical measurements, where the C4F filed-effect transistor exhibited a p-type semiconductor behavior and significantly enhanced on/off ratio. Therefore, this work provides a novel technique for the fabrication of graphene devices for promising electronic and optoelectronic applications, but also opens a route towards the tailoring and engineering of electronic properties of graphene.
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| 7. |
- Jiangwei, Liu, et al.
(författare)
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Compressive behavior and vibration-damping properties of porous Ti-6Al-4V alloy manufactured by laser powder bed fusion
- 2021
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Ingår i: Journal of Manufacturing Processes. - : Elsevier BV. - 1526-6125 .- 2212-4616. ; 66, s. 1-10
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Tidskriftsartikel (refereegranskat)abstract
- Porous Ti-6Al-4V alloy with various cell geometries and cell sizes was manufactured by laser powder bed fusion (LPBF) technique, and the influence of the structural characteristics on the compressive behavior and vibrationdamping abilities was systematically investigated. In terms of the compressive performance, both elasto-brittle and elasto-plastic features are observed from the compressive stress-strain curves and the corresponding transformation from elasto-brittle to elasto-plastic can be achieved by increasing the cell size. Moreover, the compressive performances are found to be closely related to the relative density determined by both the cell geometries and cell sizes of specimens. The energy absorption capability of each cellular structure increases linearly when increasing the as-manufactured density, while the energy absorption efficiency presents sensitivities to both the cell geometry and the cell size. The results also reveal that the variation of natural frequency is proportional to the specific strength (i.e., strength-weight ratio), and the cellular structure with larger cell size exhibits better damping ability than smaller sized structures.
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| 8. |
- Li, Hu, 1986-, et al.
(författare)
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Direct measurement of the surface energy of single-walled carbon nanotubes through atomic force microscopy
- 2019
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Ingår i: Journal of Applied Physics. - : AMER INST PHYSICS. - 0021-8979 .- 1089-7550. ; 126:6
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Tidskriftsartikel (refereegranskat)abstract
- Surface energy in nanomaterials is an essential parameter demonstrating a key role in their surface interactions and their functionalization aptitude. In this work, a new and facile methodology based on atomic force microscopy for the measurement of the surface energy of single-walled carbon nanotubes (SWCNTs) is reported. The proposed approach starts with the calibration based on a well-studied material, graphite, and the precision of the technique is confirmed by the measurement of the surface energy of multiwalled carbon nanotubes. Our measurements show that SWCNTs display a surface energy of 52.8mJ/m(2), which is in very good agreement with theoretical predictions of the measured property. Our experimental approach is essentially applicable to other nano-objects in contrast to conventional wet angle methods which are currently employed mainly in bulk materials.
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| 9. |
- Li, Hu, 1986-, et al.
(författare)
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Moiré patterns arising from bilayer graphone/graphene superlattice
- 2020
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Ingår i: Nano Reseach. - : Springer Nature. - 1998-0124 .- 1998-0000. ; 13:4, s. 1060-1064
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Tidskriftsartikel (refereegranskat)abstract
- Moiré patterns from two-dimensional (2D) graphene heterostructures assembled via van der Waals interactions have sparked considerable interests in physics with the purpose to tailor the electronic properties of graphene. Here we report for the first time the observation of moiré patterns arising from a bilayer graphone/graphene superlattice produced through direct single-sided hydrogenation of a bilayer graphene on substrate. Compared to pristine graphene, the bilayer superlattice exhibits a rippled surface and two types of moiré patterns are observed: triangular and linear moiré patterns with the periodicities of 11 nm and 8–9 nm, respectively. These moiré patterns are revealed from atomic force microscopy and further confirmed by following fast Fourier transform (FFT) analysis. Density functional theory (DFT) calculations are also performed and the optimized lattice constants of bilayer superlattice heterostructure are in line with our experimental analysis. These findings show that well-defined triangular and linear periodic potentials can be introduced into the graphene system through the single-sided hydrogenation and also open a route towards the tailoring of electronic properties of graphene by various moiré potentials.
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| 10. |
- Liu, Jiangwei, et al.
(författare)
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Experimental observation of size-dependent behavior in surface energy of gold nanoparticles through atomic force microscope
- 2018
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Ingår i: Applied Physics Letters. - : AMER INST PHYSICS. - 0003-6951 .- 1077-3118. ; 113:8
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Tidskriftsartikel (refereegranskat)abstract
- Surface energy plays a key role in the physicochemical interactions of material surfaces, and it is closely related to the unique properties and numerous surface functionalization possibilities of gold nanoparticles. Herein, we have reported an atomic force microscopy based technique to measure the surface energies of different materials in the peakforce quantitative nanomechanical mapping mode. Our study on gold nanoparticles focuses on the particles with diameters ranging from 2 to 14 nm. The experimental results indicate a clear size-dependent behavior in the surface energy of gold nanoparticles when the size is smaller than 5 nm, and the smallest gold nanoparticle displays a threefold higher surface energy compared to bulk gold. Therefore, our experimental results provide essential evidence that can lead to a better understanding of the size-property relationships allowing for process design in gold nanoparticles.
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