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排序方式: 共有4177条查询结果,搜索用时 15 毫秒
1.
Gui-Yang Luo Yi-Jing Gu Yuan Liu Zi-Liang Chen Yong-lin Huo Fu-Zhong Wu Yi Mai Xin-Yi Dai Yong Deng 《Ceramics International》2021,47(8):11332-11339
LiFePO4 modified by N-doped graphene (NG) with a three-dimensional conductive network structure was synthesized via a one-step in situ hydrothermal method. The effects of N amount of NG on the phase structure, morphology, and electrochemical properties of LiFePO4 are investigated in this study. X-ray diffraction (XRD) results show that doping suitable N amounts in NG do not alter the crystal structure of LiFePO4, and scanning electron microscopy (SEM) images show that NG can slightly reduce the particle size of LiFePO4. The high-resolution transmission electron microscopy (HRTEM) results show that the LiFePO4 particles are well covered and connected by NG. The electrochemical performance confirms that LiFePO4 modified by 20% N-doped graphene (named LFP/NG-4) displays a perfect specific capacity of 166.6 mAh·g?1 at a rate of 0.2C and can reach 125 mAh·g?1 at a rate of 5 C. Electrochemical impedance spectroscopy (EIS) results illustrate that the charge transfer resistance value of the LFP/NG-4 composite is only 58.6 Ω, which is very low compared with LiFePO4. Cyclic voltammetry (CV) tests indicate that the addition of 20% N-doped graphene can effectively reduce electrode polarization and improve reversibility. The LFP/NG-4 composite with a three-dimensional conductive network structure can be regarded as a promising cathode material for Li-ion batteries. 相似文献
2.
Sijia Huo Yujin Wang Mianyi Yao Zhikun Zhang Lei Chen Hui Gu Jiahu Ouyang Yu Zhou 《Journal of the European Ceramic Society》2021,41(11):5466-5473
Novel TiC-based composites were synthesized by reactive hot-pressing at 1800 °C for 1 h with ZrB2 addition as a sintering aid for the first time. The effects of ZrB2 contents on the phase composition, microstructure evolution, and mechanical properties were reported. Based on the reaction and solid solution coupling effects between ZrB2 and TiC, the product ZrC may be partially or completely dissolved into the TiC matrix, and then phase separation within the miscibility gap is observed to form lamellar nanostructured ZrC-rich (Zr, Ti)C. The TiC-10 mol.% ZrB2 (starting batch composition) exhibits good comprehensive mechanical properties of hardness 27.7 ± 1.3 GPa, flexural strength 659 ± 48 MPa, and fracture toughness of 6.5 ± 0.6 MPa m1/2, respectively, which reach or exceed most TiC-based composites using ceramics as sintering aids in the previous reports. 相似文献
3.
Zi-Zi Li Lei Lei Min-Xi Huo Zi-Rui Liu Xin-Quan Yang Yu-Lin Wang Yang Yuan 《International Journal of Food Science & Technology》2021,56(1):269-277
The objective of this paper was to investigate the complex of grape seed procyanidins (GSP) with zein hydrolysate (ZH). The interaction was determined using isothermal titration calorimetry (ITC) and fluorescence spectroscopy. The particle size, ζ-potential, scanning electronic microscopy (SEM) and stability test of the ZH-GSP complex were measured. The results of ITC, particle size and SEM suggested that there was a hydrogen bond-dominated interaction between GSP and ZH, and the ZH-GSP complex presented as a spherical shape with particle size of 234 nm, polydispersity index of 0.11 and ζ-potential of −46.4 mV. The results of the fluorescence spectroscopy showed that the fluorescence quenching effect of GSP on ZH was GSP concentration-dependent and the quenching process was mainly static quenching. The ZH-GSP complex had better physical stability in aqueous solution, and their solution was more stable than GSP solution under illumination and high-temperature treatment at 75°C. 相似文献
4.
Xiaopu Lyu Yunxi Huo Jin Yang Dawen Yao Kaimin Li Haoxian Lu Yangzong Zeren Hai Guo 《Indoor air》2021,31(5):1340-1352
Due to the high health risks associated with indoor air pollutants and long-term exposure, indoor air quality has received increasing attention. In this study, we put emphasis on the molecular composition, source emissions, and chemical aging of air pollutants in a residence with designed activities mimicking ordinary Hong Kong homes. More than 150 air pollutants were detected at molecular level, 87 of which were quantified at a time resolution of not less than 1 hour. The indoor-to-outdoor ratios were higher than 1 for most of the primary air pollutants, due to emissions of indoor activities and indoor backgrounds (especially for aldehydes). In contrast, many secondary air pollutants exhibited higher concentrations in outdoor air. Painting ranked first in aldehyde emissions, which also caused great enhancement of aromatics. Incense burning had the highest emissions of particle-phase organics, with vanillic acid and syringic acid as markers. The other noteworthy fingerprints enabled by online measurements included linoleic acid, cholesterol, and oleic acid for cooking, 2,5-dimethylfuran, stigmasterol, iso-/anteiso-alkanes, and fructose isomers for smoking, C28-C34 even n-alkanes for candle burning, and monoterpenes for the use of air freshener, cleaning agents, and camphor oil. We showed clear evidence of chemical aging of cooking emissions, giving a hint of indoor heterogeneous chemistry. This study highlights the value of organic molecules measured at high time resolutions in enhancing our knowledge on indoor air quality. 相似文献
5.
Xiao-Li Fan Yuan-Fang Huo Chang-Yang Li M.Bobby Kannan Xiao-Bo Chen Shao-Kang Guan Rong-Chang Zeng Quan-Li Ma 《稀有金属(英文版)》2019,(6)
A hexagonal nanosheet Mg(OH)_2 coating was prepared through a one-step hydrothermal method using LiOH solution as mineralizer and then modified by ethylenediaminetetraacetic acid(EDTA) to minimize the rapid corrosion of AZ31 Mg alloy.The performance of the coating was evaluated using electrochemical technique,hydrogen evolution measurements, nanoscratch test,Fourier-transform infrared spectroscopy(FTIR), X-ray diffraction(XRD) patterns and field-emission scanning electron microscopy(FESEM).The results suggested that the corrosion rate of bare AZ31 Mg alloys was significantly reduced by one and two orders of magnitude through the protection from Mg(OH)_2 coating and modification with EDTA(i.e., EDTA-Mg(OH)_2 coating), respectively.FESEM micrographs indicated that the modification in EDTA elicits to the formation of an EDTA-Mg(OH)_2 composite with a thickness as twice as that of as-prepared Mg(OH)_2 coating.Nanoscratch tests revealed strong adhesion between the composite or Mg(OH)_2 coating and the substrate.The study of formation and corrosion mechanisms of the coatings manifested that Mg(OH)_2 was first formed near the intermetallic compound AlMn particles and gradually covered the entire surface, wherein the AlMn particles played an important role in the coating growth process.And it also proved that EDTA accelerated the formation of Mg(OH)_2. 相似文献
6.
7.
针对磨矿仓布料小车倒仓下料为远程半自动化模式,操作频繁且容易发生故障等问题,对布料小车进行了全自动布料的研究。通过对布料小车装置的机械、电气等自动化控制改造,解决了远程半自动化布料,实现了布料小车全自动化布料功能。 相似文献
8.
四川省植被覆盖时空演变及未来变化趋势分析 总被引:2,自引:0,他引:2
四川省地处长江上游,是长江流域重要的生态屏障;解析该区域植被覆盖的时空演变特征,对长江上游的生态环境修护与治理具有重要意义。基于长时间序列的MODIS NDVI数据,解析2000~2016年间四川省植被的空间分布格局与时间变化特征;采用趋势分析法和Hurst指数,预测未来植被的变化趋势及持续性。结果表明:(1)四川省NDVI多年平均值为0.50,植被覆盖整体上呈现川东高于川西的空间分布特征;(2)2000~2016年间,四川省的NDVI值在0.48至0.53之间波动,整体呈上升趋势,增长率为0.002 5/a;(3)植被覆盖度在未来变化将呈现改善大于退化的趋势;植被持续性改善的面积大于持续性退化的面积。 相似文献
9.
湖南省郴州市饭垄堆北段锡钨多金属矿位于湘南钨锡钼铋多金属成矿带东坡矿田内,成矿地质条件优越,具有很好的找矿前景。根据该矿床地质特征以及已有的地质矿产勘查成果,系统总结了矿区101、102、103号主矿体特征。在此基础上,进一步讨论了该类裂隙充填细脉带型锡钨多金属矿床在勘查过程中探矿工程布置的优化方法:即:①探矿工程不宜按每个矿带单独控制,应对整个赋矿层位进行整体控制;②应对含有毒砂、锡、钨细脉的岩性段进行连续取样化验,既可避免漏矿,又可以为将来工业指标调整后重新圈定矿体提供直接依据。 相似文献
10.
M.J. Wang W.T. Wang L. Liu F. Scurti Y.D. Xia B.L. Huo X. Yang Y. Zhao 《Ceramics International》2018,44(13):15572-15578
Corrosion resistance is a crucial property to achieve successful superconducting joints of Y0.5Gd0.5Ba2Cu3O7-z (YGdBCO) coated conductors (CCs). Cu and Ag metallic layers need to be fully removed from the area of conductor to be joint to allow for a superconducting path across the joint. Therefore, when using a wet etching process to remove the metallic layers, the joint performance can be significantly influenced by the etching conditions. The effects of chemical etching with ammonia water and hydrogen peroxide mixture on crystal structure, surface microstructure and critical current (Ic) of YGdBCO CCs were systematically investigated. We found the set of etching parameters that does not affect conductor performance, leaving the Ic of the YGdBCO conductor unchanged upon etching. However, when the etching conditions are not optimal, decrease in Ic was found and the underlying reasons driving the degradation were investigated. Raman spectroscopy and XRD analysis indicated that the reduced Ic is mainly due to oxygen deficiency in the YGdBCO crystal lattice. 相似文献