The organic and mineral components in two coals and resulting high-temperature ashes with high silicon content were characterized by second-derivative infrared spectroscopy, Raman spectroscopy, and X-ray diffraction (XRD). The infrared spectra of raw coals show weak organic functional groups bands but strong kaolinite bands because of the relatively high silicates content. In contrast, the Raman spectra of raw coals show strong disordered carbon bands but no mineral bands since Raman spectroscopy is highly sensitive to carbonaceous phases. The overlapping bands of mineral components (e.g., calcite, feldspar, and muscovite) were successfully resolved by the method of second-derivative infrared spectroscopy. The results of infrared spectra indicate the presence of metakaolinite in coal ashes, suggesting the thermal transformation of kaolinite during ashing. Intense quartz bands were shown in both infrared and Raman spectra of coal ashes. In addition, Raman spectra of coal ashes show a very strong characteristic band of anatase (149 cm–1), although the titanium oxides content is very low. Combined use of second-derivative infrared spectroscopy and Raman spectroscopy provides valuable insight into the analyses of mineralogical composition. The XRD results generally agree with those of FTIR and Raman spectroscopic analyses.
End-selective etching the AuNRs of AuNR@mSiO2 can be managed to produce cavity-possessing, rattle-type, hollow, and shape-adaptive silica-coated nanocomposites.
The spectrum and size controlled synthesis of gold nanorod is of great value for its widely applicable aspect ratio-dependence property of anisotropic surface plasmon resonance. Herein, 1,7-dihydroxynaphthalene with a relatively...
Zinc oxide (ZnO) has attracted increasing attention as one of the most promising n-type thermo-electric materials, but its practice use was limited by high thermal conductivity and low electrical conductivity. Therefore, we herein prepared Co-doped ZnO nanoparticles by sol-gel method and then compressed nanoparticles into bulk materials through spark plasma sintering. The thermo-electric properties, including electrical conductivity, Seebeck coefficient, thermal conductivity, and ZT value, have been investigated. We found that the substitution of Co2+ causes the decrease of bandgap and the increase of carrier concentration, thus the improvement of electrical conductivity. At the same time, the Co-induced lattice distortion and nanoparticles reduce the thermal conductivity by shortening the mean free path (MFP) of the phonons. The resultant ZT is 0.037 for Zn0.9Co0.1O, which is more than 23-fold higher than that of the pure ZnO samples.
The
global rise of antibiotic resistance of pathogenic bacteria
has become an increasing medical and public concern, which is further
urging the development of antimicrobial channels for treating infectious
diseases. The combination of photodynamic therapy (PDT) with photothermal
therapy (PTT) has been considered as a promising alternative way for
the replacement of traditional antibiotic therapy. In this research,
the newly fabricated Chlorin-e6 (Ce6) conjugated mesoporous silica-coated
AuNRs, designated AuNR@SiO2-NH2-Ce6, exhibited
synergistic photothermal effects and single oxygen localized generation
property, and showed stronger photoinactivation for bacteria compared
with Ce6. AuNR@SiO2-NH2-Ce6 can anchor to the
cell membrane and accumulate in the interior of cells. Furthermore,
the unique porous structure of AuNR@SiO2NH2 enabled
Ce6 encapsulation in the mesopores and was subsequently released and
activated by photothermic effect, allowing the generated single oxygen
to penetrate into the cytoplasmic membrane or directly enter the interior
of bacteria cells, thus overcoming the inherent defects of single
oxygen. AuNR@SiO2-NH2-Ce6 not only damaged the
integrity of the cell membrane of bacteria but also facilitated the
cellular permeation and accumulation of external nanoagents in the
bacteria upon light irradiation. In addition, AuNR@SiO2-NH2-Ce6 exhibited negligible cytotoxicity toward mammalian
cells and hemolytic activity. Therefore, AuNR@SiO2-NH2-Ce6 may be highly promising candidates as topical antibacterial
agents, and this study has wide implications on the design of next-generation
antimicrobial agents.
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