Morphology and Photoluminescence of HfO2Obtained by Microwave-Hydrothermal

In this letter, we report on the obtention of hafnium oxide (HfO2) nanostructures by the microwave-hydrothermal method. These nanostructures were analyzed by X-ray diffraction (XRD), field-emission gum scanning electron microscopy (FEG-SEM), transmission electron microscopy (TEM), energy dispersive X-ray spectrometry (EDXS), ultraviolet–visible (UV–vis) spectroscopy, and photoluminescence (PL) measurements. XRD patterns confirmed that this material crystallizes in a monoclinic structure. FEG-SEM and TEM micrographs indicated that the rice-like morphologies were formed due to an increase in the effective collisions between the nanoparticles during the MH processing. The EDXS spectrum was used to verify the chemical compositional of this oxide. UV–vis spectrum revealed that this material have an indirect optical band gap. When excited with 488 nm wavelength at room temperature, the HfO2nanostructures exhibited only one broad PL band with a maximum at around 548 nm (green emission)

Numerical analysis of the spectral response of an NSOM measurement

Near-field Scanning Optical Microscopy (NSOM) is a powerful tool for investigating optical field with resolution greater than the diffraction limit. In this work, we study the spectral response that would be obtained from an aperture NSOM system using numerical calculations. The sample used in this study is a bowtie nanoaperture that has been shown to produce concentrated and enhanced field. The near- and far-field distributions from a bowtie aperture are also calculated and compared with what would be obtainable from a NSOM system. The results demonstrate that it will be very difficult to resolve the true spectral content of the near-field using aperture NSOM. On the other hand, the far-field response may be used as a guide to the near-field spectrum

To show is to know? The conceptualization of evidence and discourses of vision in social science and education research

The demand for evidence in particular forms shapes contemporary educational policy, curriculum studies’ debates over the politics of knowledge “versus” wisdom, and research into classroom practice. This paper provides a genealogical trace that examines the arbitrary and historical linkage of discourses of vision (especially when vision becomes visuality) and the conceptualization of evidence (especially when evidence becomes empiricism-as-density). The analysis elaborates two counter-memories of post-ocular and post-empiricist debates over truth claims that educators have engaged amid the formation of Western social sciences. The counter-memories open consideration of the uneven legacies, politics and problems operating through forms of rationality now popular in ethico-redemptive sciences. The final section links nodal points in historical debates to the rethinking of evidence and vision in contemporary movements such as big data and mindfulness practices. The paper concludes with consideration of the changing, polarizing and reiterative aspect of networked power and different tactics of reason that social science, educational and curriculum inquiry face in the twenty-first century