JOURNAL OF THE CHINESE CHEMICAL SOCIETY
·
2024
·
IF 1.6
Ying Wang,Lan Huang,Zhenfeng Tian,Shaolin Ge,Bing Zhang,Zhao Zhang,Mingxi Chen,Bingxia Xu,Jinghang Hao,Jun Yang
As the main structural component of tobacco cell wall, lignin content is an important factor affecting the safety of tobacco smoking. However, it is time-consuming to quantify lignin by conventional wet chemical analysis methods. In this work, a 13 C multiCP/MAS NMR spectral analysis method for tobacco lignin was established. The multiCP/MAS NMR sequence was optimized for tobacco lignin. The optimized nuclear magnetic sequence parameters were 9 CP cycles of 1.5 ms, repolarization time of 0.7 s, and a total acquisition time of 130 min. Subsequently, TMSP was used as the internal standard substance to establish the working curve, and the correlation coefficient was 0.9946. The relative standard deviation (RSD, n = 5) was 3.26%. This method was applied to the determination of lignin content in different types of tobacco samples. The relative error in the determination of lignin content by this method did not exceed 4.46% compared to the results of the chemical method. The results showed that the 13 C multiCP/MAS NMR spectral analysis method had the advantages of accuracy and rapidity, which provided a new technical means for the quantitative study of tobacco cell wall substances.
研究领域:
植物化学
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烟草科学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF COLLOID AND INTERFACE SCIENCE
·
2021
·
IF 8.128
Runrun Cheng,Yan Wang,Xiaochuang Di,Zhao Lu,Ping Wang,Mingliang Ma,Jinrui Ye
Nowadays, facing the inevitable electromagnetic (EM) pollution caused by many electronic products, it is urgent to develop high-performance microwave absorbing materials. In particular, the bimetallic carbon-based composites derived from MOFs exhibit excellent microwave absorption potential due to their simple preparation, low cost, adjustable morphology and magnetoelectric synergy mechanism. In this work, we successfully prepared plum-like NiCo@C composite by simple solvothermal method and carbonization treatment, which displays strong absorption (-55.4 dB) and wide effective absorption band (EAB, 7.2 GHz) when the loading is 20 wt%. The plum-like structure greatly enriches the non-uniform interface and the structural anisotropy contributes to the dissipation of electromagnetic waves . At the same time, the band hybridization and magnetic coupling of NiCo@C contribute to the coordination of EM characteristics. Overall, this work proves the feasibility of NiCo@C hierarchical composite in the field of microwave absorbing, and provides insight for the development of high-performance absorbers.
研究领域:
材料科学
·
电磁学
✓ 已验证
DOI
高影响因子
ACTA MATERIALIA
·
2025
·
IF 9.3
Liang Yan,Yujing Zhang,Yilin Zhang,Pan Ying,Chuyang Liu,Jie Jiang,Xiaopeng Li,Dong-Hyun Kim,Zhi Zhang,Feng Xu,Zhihui Zeng
The polarization effect has been unequivocally demonstrated to markedly enhance the microwave absorption performance. However, the pursuit of achieving broadband absorption through meticulously designed polarization behavior continues to pose a formidable challenge. In this work, we present a unique multi-polarization strategy in the La(OH) 3 /N-doped rGO composites, incorporating dipole polarization induced by nitrogen doping and intrinsic defects, homogeneous interfacial polarization contributed by locally crystalized nano-domains in La(OH) 3 , and heterogeneous interfacial polarization at the heterojunctions between La(OH) 3 and N-doped rGO, to significantly enhance the multi-band polarization loss. Experimental and theoretical investigations reveal that the La(OH) 3 /N-doped rGO hybrid featuring distinctive crystalline/amorphous nano-domains exhibits remarkable coupling effects, encompassing an enhanced electron transport rate and strengthened interfacial electron interactions. The improved electron transport is attributed to increased electron transitions at heterojunctions with matched Fermi levels and enhanced charge conduction from the crystalline regions within La(OH) 3 . Furthermore, strong polarization relaxation at these heterojunction interfaces, along with weaker but significant polarization at numerous homogeneous interfaces, contributes to the enhanced interactions. Consequently, an exceptional minimal reflection loss of -69.6 dB has been achieved, accompanied by an impressive effective absorption bandwidth of 7.7 GHz, which surpasses that of the current state-of-the-art microwave absorbers. This work unveils an innovative design paradigm aimed at the meticulous regulation of polarization loss, thereby laying a robust foundation for the advancement of high-performance absorbers.
研究领域:
材料科学
·
电磁学
✓ 已验证
产品关联
DOI
高影响因子
Materials Today Nano
·
2024
·
IF 8.2
Huimin Liu,Zhiheng Wei,Hanxu Sun,Jinjin Dang,Zhaofan He,Jin Liang,Qiang Zhuang,Jie Kong
Magnetoelectric composite is an effective strategy for increasing microwave attenuation and optimizing impedance matching to improve the electromagnetic wave (EMW) absorption properties of microwave absorbers. However, establishing the relationship between the composition, structure, and properties of magnetoelectric coupling materials remains a challenge. Herein, cobalt/N-doped carbon (Co/NC) with multiple interfaces was designed and prepared by a magnetoelectric synergistic strategy. The Co/NC composites exhibited an effective absorption bandwidth of 7.68 GHz at a low filler loading of 15 wt%. At a matching thickness of 3.5 mm, the minimum reflection loss reached −54.0 dB. In the RCS simulation, the Co/NC coating exhibited remarkable radar stealth properties, maintaining RCS values below −20 dB m 2 across all angles. Furthermore, density functional theory calculations and electron holography were applied to confirm that the excellent EMW absorption properties of Co/NC were primarily stem from the integration of multi-polarization and microscale magnetic coupling. Collectively, these findings highlight the magnetoelectric synergistic effect and interface coupling response mechanism in Co/NC heterostructures, offering a viable strategy for developing high-performance magnetoelectric composite microwave absorbers.
研究领域:
材料科学
·
电磁学
✓ 已验证
DOI
高影响因子
ADVANCED FUNCTIONAL MATERIALS
·
2024
·
IF 18.5
Gang Fang,Chuyang Liu,Meng Xu,Xiaohan Zhang,Yue Wu,Dong-Hyun Kim,Guangbin Ji
Anion defect engineering is proven to be an efficient approach to reconstruct the electronic configuration of carbon-based magnetoelectric materials for targeted modulation of electromagnetic (EM) performance. However, traditional mono-anionic doping suffers from low defect concentration and lacks diverse polarization mechanisms. In this work, multi-anions (N/S/F) stepwise-doped carbon/Fe 3 C magnetoelectric composites are elaborately constructed, wherein the predesigned N defects serve as activated sites for anomalously adopting S anions (Step I) and subsequent F anions (Step II) in non-marginal areas of the carbon layer. It is found that S prefers to replace pyrrolic N defects while F tends to form dangling bonds with the C site adjacent to the pyridinic N. Intriguingly, besides the inherent polarized resonance of N defect at ≈15 GHz, customized S and F defects induce new polarization resonances at ≈10 GHz and ≈15+ GHz, respectively. Under a typical multi-polarization effect with the synergetic magnetic response, the carbon/Fe 3 C composites with N/S/F defects harvest the broadest bandwidth of 8.28 GHz (9.72–18 GHz) at 2.55 mm, covering a wide frequency range almost from X to Ku bands. This work demonstrates the positive impact of localized multi-defects customization and multi-polarization effect on expanding microwave absorption bandwidth, providing valuable insights for the advanced design of ultra-broadband absorbers.
研究领域:
材料科学
·
电磁学
✓ 已验证
产品关联
DOI
高影响因子
ADVANCED FUNCTIONAL MATERIALS
·
2021
·Vol. 32
·期 8
·2110665
·
IF 18.808
Bin Ze Yang,Ping Xie,Qin Luo,Zhi Wei Li,Cai Ying Zhou,Yan Hong Yin,Xian Bin Liu,Ye Sheng Li,Zi Ping Wu
Lithium–sulfur batteries (LSBs) have tremendous attractive interest for their high theoretical energy density, natural abundance, and environmental friendliness. However, the commercialization remains constrained by the shuttle effect and sluggish kinetics of polysulfides. Herein, a spraying/discharging strategy is employed to fabricate binder-free ω-Li 3 V 2 O 5 (ω-LVO) catalytic network with multi-polarization centers by intercalating Li-ions into tetrahedral V 2 O 5 for addressing the mentioned issues. Li (0.51 eV) and V (0.57 eV), which have a strong positive electric potential, and O (−0.57 eV), which has a strong negative electric potential, exhibit high polarity that can capture polysulfides effectively. In addition, the amounts of the polarity sites would be significantly increased because the catalyst is composed of light elements. Therefore, the ω-LVO octahedron can catalyze polysulfides to short-chains sufficiently. The blue shift in synchronous ultraviolet-visible spectra and ultra-low Tafel plots of 34 and 20 mV dec −1 at two discharge plateaus demonstrate excellent kinetics behavior even with a low catalyst loading. Furthermore, the conductive networks facilitate electronic/ionic transmission and thereby boost their electrochemical performances. This work offers an efficacious method to promote kinetics behaviors and lessen the gap between theoretical specific capacities and future commercialization of LSBs.
研究领域:
电化学
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能源材料
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纳米催化
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电池技术
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功能材料
✓ 已验证
DOI
高影响因子
ADVANCED FUNCTIONAL MATERIALS
·
2025
·
IF 19
Mengjia Shi,Zirui Jia,Di Lan,Zhenguo Gao,Siyuan Zhang,Guanglei Wu
Designing and constructing built-in electric field (BIEF) between substances is an effective way to enhance multi-polarization relaxation. Ni 3 S 4 @Co 4 S 3 /Ni 3 N@Co 2 N 0.67 (NC-S/NC-N) composites are prepared through multiple hydrothermal and nitriding steps. The influence of the BIEF constructed by the Type-II heterojunction between the corresponding substances on the wave absorption performance is investigated. A BIEF model is constructed for this material, and the transfer mechanism of electrons and holes in the BIEF is studied. The crystal structure, lattice parameters, unit cell volume, and phase composition of composites are quantitatively analyzed by XRD refinement using the Rietveld method. The electronic structure of the heterointerface is studied by using density functional theory (DFT) calculations to verify the characteristics of Type-II heterojunctions and the formation of BIEF. The BIEF constructed by Type-II heterojunction enhances the interfacial polarization intensity by regulating the interfacial charge distribution, accelerates carrier transport, and increases conductive loss. It also affects magnetic loss by modulating the spin polarization of Ni/Co magnetic components. When the matching thickness is 2.1 mm, the minimum reflection loss (RL min ) can reach −51.64 dB. Meanwhile, the maximum effective absorption bandwidth (EAB max ) can cover 5.12 GHz at 2.3 mm. The results show that the microscopic interface mechanisms provides a brand-new path.
研究领域:
材料科学
·
凝聚态物理
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电磁功能材料
·
纳米复合材料
·
能量存储与转换
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）