Search

Wavelength converters in white light‐emitting diodes are usually made by sintering of phosphor‐glass powder compacts. An issue is that the sintering process usually results in the reduction of phosphor amount. In the present study, composites containing CaAlSiN3:Eu2+ red phosphor and Bi2O3‐B2O3‐ZnO‐Sb2O5 glass were fabricated by sintering method. Influences of CaAlSiN3:Eu2+ phosphor content (10 vol%–30 vol%) and sintering temperature (410–430°C) on the residual amount of the phosphor phase and the resulting luminescence intensity of the composites were investigated. The change of CaAlSiN3:Eu2+ content due to sintering was analyzed by X‐ray diffraction. The interdiffusion between the CaAlSiN3:Eu2+ and glass matrix was examine by scanning electron microscope equipped with energy dispersive X‐ray spectrometry. This paper focuses on the change of luminescence intensity after sintering. It was found that although the content of phosphor CaAlSiN3:Eu2+ reduces after sintering; the luminescent intensity of the composites anomalously increases. The optimum luminescence intensity is 14% higher than that of the as‐mixed, unfired powder. It is proposed that the incorporation of Bi3+ ions from the glass matrix into the phosphor CaAlSiN3:Eu2+ during sintering improves the luminescence ability of the phosphor particles. [ABSTRACT FROM AUTHOR]

By using coal fly ash as a raw material and graphite as a reducer in the protective atmosphere of argon,SiC/Al2O3 composite materials were synthesized by carbothermal reduction.The reaction process of reduction of the coal fly ash was studied,and its influencing factors were investigated.The composition of products obtained at different temperatures was analyzed by X-ray diffraction,and the microstructure was observed by scanning electron microscopy and energy dispersive spectroscopy.The results show that the phases of quartz and mullite in the coal fly ash are almost completely reactive at 1673 and 1773 K,respectively.With increasing temperature,the contents of SiC and Al2O3 increase,and the suitable temperature condition is 1773 to 1873 K.The extension of holding time is good for the formation of SiC and Al2O3,and the appropriate holding time is 3 to 4 h.Increasing the carbon content has positive effect on the formation of SiC and Al2O3,and the optimum molar ratio of C/Si is 4 to 5.In the prepared SiC/Al2O3 composite materials,SiC is homogeneously dispersed in the products,and its granularity is less than 20 μm.

We report the fabrication of Pt@SnO2 nanoparticles using a sol–gel method. These nanoparticles are used as a sensing material. The structural and morphological characterization of the prepared Pt@SnO2 nanoparticles was performed using ultraviolet–visible spectroscopy, X‐ray diffraction, transmission electron microscopy, and energy‐dispersive X‐ray spectroscopy. The sensor responses of SnO2 and 1 wt% Pt/SnO2 to 1% hydrogen gas (H2) were 1.3 and 1.9, respectively. The sensor response of a Pt@SnO2 core–shell sensor increased to 5.1 at room temperature; it improved by 3.9 times compared to SnO2 and by 2.7 times compared to 1% Pt/SnO2 in sensing 1% H2. The response time for the prepared Pt@SnO2 sensor was also shortened by 2.0 and 1.4 times compared to SnO2 and 1 wt% Pt/SnO2, respectively. The sensor response increased rapidly from 1.4 to 5.1, with an increase in H2 concentration from 800 to 10,000 ppm (1%). We investigated the H2‐sensing mechanism of Pt@SnO2. [ABSTRACT FROM AUTHOR]

Eosinophilic granulomatosis with polyangiitis is a systemic vasculitis. It could affect respiratory system, kidney, and central nervous system frequently; however, all body organs could be involved. Asthma and eosinophilic pneumonia are predominant manifestations in respiratory system. Bronchoalveolar lavage or lung biopsy may be used for diagnosis, but endobronchial lesion is not considered as a manifestation of eosinophilic granulomatosis with polyangiitis. Here we present a case of eosinophilic granulomatosis with polyangiitis with unusual endobronchial lesion which was confirmed by endobronchial biopsy. [ABSTRACT FROM AUTHOR]