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81.
82.
Porous anodic alumina (PAA) was used as a template to prepare Co nanowires array from 1-ethyl-3-methylimidazolium chloride ionic liquid by direct current method. The surface morphology of porous anodic alumina template was observed by field emission-scanning tunneling microscopy (FE-SEM) before and after the electrodeposition of Co nanowires. The electrodeposition of Co nanowires was characterized by transmission electron microscopy (TEM) and X-ray powder diffraction (XRD). TEM results indicate that the Co nanowire surface is coarse and porous when aqueous solution was used as electrolyte, and the Co nanowire deposited from the ionic liquid is uniform and smooth. XRD results show that the electrodeposition of Co is a mixture of crystal and microcrystal phase. 相似文献
83.
首先采用溶液法在碳布上生长Co-MOF二维纳米片,通过高温退火和刻蚀后得到MOF衍生多孔碳纳米片。以Co-MOF衍生的多孔碳纳米片/碳布(CNS/CC)作为碳基骨架,采用电化学沉积法负载高活性氮掺杂石墨烯量子点(N-GQDs),制备得到分级多孔结构的N-GQD/CNS/CC复合材料。组装成自支撑且无粘结剂的N-GQD/CNS/CC电极,当电流密度为1 A·g~(-1)时,其比电容高达423 F·g~(-1)。通过储能机制和电容贡献机制的研究表明,在碳纤维上原位生长的具有高双电层电容的CNS和表面负载具有高赝电容的N-GQDs之间相互协同作用,使得N-GQD/CNS/CC电极具有高电容性能,是一种理想的超级电容器电极材料。电极材料的高导电、分级多孔结构有利于电子的传输和电解质离子的扩散,具有良好的动力学性能,能快速充放电和具有优异的倍率特性。将电极组装成对称型超级电容器,功率密度为250 W·kg~(-1)时对应的能量密度达到7.9 Wh·kg~(-1),且经过10 000次循环后电容保持率为91.2%,说明氮掺杂石墨烯量子点/MOF衍生多孔碳纳米片复合材料是一种电化学性能稳定的具有高电容性能的全碳电极材料。 相似文献
84.
Chemical Modification of Silica Gels 总被引:2,自引:0,他引:2
Highly porous pure and polyethyleneglycol (PEG)-doped silica gels have been prepared from tetraethyl orthosilicate (TEOS) in ethanol using NH4OH base-catalysis. Addition of PEG to the SiO2-system increases the average particle size and most frequent pore diameter of the resultant gels while their total surface area decreases. The viscosity of the sol increases with PEG concentration and passes through a maximum with increasing molecular weight at PEG 200. Results obtained indicate a definite interaction of the polymer with SiO2 and that this interaction is not as a result of direct formation of Si– O– C linkage, but is more likely to be due to hydrogen bonding between the hydrated PEG and the Si– O– Si network. Structure-process correlations are considered. 相似文献
85.
Porous SiO2 films were successfully deposited on silicon substrates by a modified base-catalyzed Sol-Gel process (MBCP) containing polyvinyl alcohol (PVA). The process conditions, such as the gelation time, the synthesis temperature, the stabilizing agent of the precursor solution and the spin coating speed, the heat-treatment, the annealing temperature of the film on the microstructure and porosity of porous SiO2 films were systematically investigated by SEM, XRD and ellipsometry techniques. This study provides a novel preparation technique for the porous SiO2 film. Using this process, the resultant film can reach a thickness of 3.6 m for one layer, a porosity of 25–50%, a low thermal conductivity of 0.11 W/m·K. This film will be used as a low dielectric layer, an thermal-insulating layer and a low refractive index layer. 相似文献
86.
《Arabian Journal of Chemistry》2022,15(7):103933
In this study, a fingerprint-activity relationship modeling between chemical fingerprints and antirheumatic activity was established, and multivariate statistical analysis was used to evaluate the quality of Taxilli Herba (TH) from different hosts. Characteristic fingerprints of 20 batches of TH samples were generated by high-performance liquid chromatography coupled with triple quadrupole-time of flight tandem mass spectrometry (HPLC-Triple TOF-MS/MS), and the similarity analysis was calculated based on thirteen common characteristic peaks by hierarchical clustering analysis (HCA). Subsequently, nine efficacy markers were discovered by combining fingerprints and antirheumatic activity through grey correlation analysis (GCA) and bivariate correlation analysis (BCA). Meanwhile, the content of 5 constituents in 9 markers was determined by high-performance liquid chromatography coupled with triple quadrupole-linear ion trap tandem mass spectrometry (HPLC-QTRAP-MS/MS). The comprehensive quality of TH was assessed using multivariate statistical analysis, including principal components analysis (PCA) and technique for order preference by similarity to ideal solution (TOPSIS). The results showed that a high dose of TH extract could markedly ameliorate arthritis damage compared to other doses, with flavonoids playing an important role in the antirheumatic activity. The comprehensive quality of samples from Morus alba L. (SS) was superior to those from Liquidambar formosana Hance (FXS). The present study will demonstrate the markers associated with efficacy, and provide an applicable strategy for more comprehensive quality control and evaluation of TH. 相似文献
87.
POROUS MEMBRANE TEMPLATED SYNTHESIS OF POLYMER PILLARED LAYER 总被引:5,自引:0,他引:5
The anodic porous alumina membranes with a definite pore diameter and aspect ratio were used as templates tosynthesize polymer pillared layer structures. The pillared polymer was produced in the template membrane pores, and thelayer on the template surfaces. Rigid cured epoxy resin, polystyrene and soft hydrogel were chosen to confirm themethodology. The pillars were in the form of either tubes or fibers, which were controlled by the alumina membrane pore surface wettability. The structural features were confirmed by scanning electron microscopy results. 相似文献
88.
Toshiharu Okui Yuriko Saito Tatsuya Okubo Masayoshi Sadakata 《Journal of Sol-Gel Science and Technology》1995,5(2):127-134
Selective gas permeation of porous organic/inorganic hybrid membranes via sol-gel route and its thermal stability are described. Separation performance of the hybrid membrane was improved compared with porous membranes governed by the Knudsen flow, and gas permeability was still much higher than that through nonporous membranes. Additionally, it was shown that these membranes were applicable at higher temperatures than organic membranes.SEM observation demonstrated that the thin membrane was crack-free. Nitrogen physisorption isotherms showed the pore size was in the range of nanometers. Gas permeability through this membrane including phenyl group was in the range of 10–8 [cc(STP) cm/(cm2 s cmHg)] at 25°C. The ratios of O2/N2 and CO2/N2 were 1.5 and 6.0, respectively, showing the permeation was not governed by the Knudsen flow. The permeability decreased as the temperature increased. Furthermore, the specific affinity between gas molecules and surface was observed not only in the permeation data of the hybrid membranes but in the physisorption data. These results suggested that the gas permeation through the hybrid membrane was governed by the surface flow mechanism.Thermal analysis indicated that these functional groups were still stable at higher temperatures. The phenyl group especially remained undamaged even at 400°C. 相似文献
89.
90.