CARBON
·
2025
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IF 11.6
Yanfeng Li,Linyue Hu,Wenmiao Wang,Pan Luo,Yang Yang,Huacheng Zhu,LiPing Yan,Yanping Zhou
Understanding the microwave dissipation mechanisms in materials is essential for the design of high-performance absorbers. Previous studies in this field have largely relied on a single-order Debye model combined with nonlinear least squares (NLLS) fitting, under the assumption of frequency-independent conductivity. However, this approach presents several limitations, including limited applicability to composite materials, inaccuracies in conductivity estimation, high sensitivity to initial guesses, and challenges in determining relaxation times. To address these issues, a multi-order Debye model that integrates Jonscher's power-law dielectric response, thereby establishing a frequency-dependent relationship for conductivity, is developed as the analytical framework. Subsequently, a distribution of relaxation times (DRT) method with Tikhonov regularization is developed to extract polarization relaxation times, with its parameter optimized based on the materials' physicochemical properties. Furthermore, a genetic algorithm (GA)-assisted NLLS fitting procedure is implemented for complex permittivity modeling, which facilitates escape from local minima and improves the likelihood of finding global optima. Dielectric analysis of the synthesized VN@N-rGO core-shell nanobelts indicates a significant synergy between the components, enhancing both conductive and polarization losses. The hybridization increases the equivalent dipole relaxation times of N-rGO, thereby aligning them more closely with the period of 2–18 GHz microwaves and thus improving polarization loss. By optimizing the VN/N–rGO ratio and layer structure, an effective absorption bandwidth of 7.7 GHz is achieved at 2.1 mm.
研究领域:
材料科学
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电磁功能材料
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微波吸收
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介电谱分析
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纳米复合材料
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计算材料分析
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF MATERIALS SCIENCE
·
2026
·
IF 4.4
Liu Tong,Zhang Jie,An Qianqian,Wu Yusheng,Li Laishi,Fang Tiehui,You Junhua
Electrocatalytic water splitting is a clean and sustainable method for hydrogen production. Cobalt diselenide (CoSe 2 ) is an electrocatalyst with great application prospects. However, due to the inherent low electrical conductivity and aggregation tendency of transition metal selenides, their practical applications are limited. In this study, under the constraint of three-dimensional porous nitrogen-doped reduced graphene oxide/nickel foam (N-rGO/NF) substrates, small-sized nitrogen-doped cobalt diselenide (CoSe 2-x N x ) nanoneedles were prepared by a one-step hydrothermal method, and excellent electrocatalysts were obtained. The optimized catalyst (N-rGO/CoSe 2-x N x /NF-100) exhibits excellent OER performance in an alkaline environment at current densities of 10, 50 and 100 mA cm −2 . N-rGO/NF not only provides good electrical conductivity for the electrocatalyst, but also limits the size of CoSe 2 . The three-dimensional porous structure constructed by small-sized CoSe 2 nanoneedles increases the specific surface area of the electrocatalyst, which is conducive to the OER process. The doping of nitrogen in CoSe 2 forms Co-Nx electron transfer channels, accelerating charge transfer. Density functional theory (DFT) calculations have confirmed that structural modification methods such as limiting the size of the electrocatalyst to avoid agglomeration, as well as electronic control methods such as nitrogen doping, can accelerate the surface structure reconstruction process of the catalyst, thereby improving the adsorption energy of the electrocatalyst for OER intermediates and reducing the overpotential.
✓ 已验证
DOI
高影响因子
TALANTA
·
2023
·
IF 6.1
Mengjiao Li,Yu Wu,Chenxi Ke,Zichen Song,Meie Zheng,Qingjie Yu,Hongda Zhu,Huiling Guo,Hongmei Sun,Mingxing Liu
In this study, an ultrasensitive unlabeled electrochemical immunosensor for the detection of cardiac troponin I (cTnI) was developed based on Pt/Au modified B,S,N co-doped reduced graphene oxide (Pt/Au–B,S,N-rGO) as a signal amplification platform. First-principles calculations were employed to analyze the electron density of states of Pt/Au–B,S,N-rGO, revealing an increase in the electron density of the graphene oxide (GO) states. Furthermore, scanning electron microscopy (SEM), X-ray photoelectron diffraction spectroscopy (XPS), and electrochemical detection were used to successfully construct and analyze Pt/Au–B,S,N-rGO. The results showed that B,S,N-rGO exhibited good electrochemical activity, and the Au/Pt NPs demonstrated excellent catalytic properties, which provided a strong foundation for achieving high-sensitivity detection. Moreover, the constructed unlabeled electrochemical immunosensor had an ideal linear range (0.1 pg/mL∼50 ng/mL) and detection limit (0.082 pg/mL). In human serum detection, the results of this immunosensor were essentially similar to the ELISA results for the same samples, which suggested that the immunosensor had a promising clinical application prospect for the detection of cTnI.
研究领域:
生物医学工程
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材料科学
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临床检验
✓ 已验证
产品关联
DOI
PubMed
高影响因子
危险品化学品经营许可证（带存储）