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The accumulation and distribution of electron-induced secondary electrons around epoxy resin are studied using electron holography. The distribution of secondary electrons is determined to be sensitive to the surface conditions of the epoxy resin, particularly to the presence of conductive materials on the surface that are introduced during specimen preparation processes. These results provide a deeper understanding of the charging and discharging mechanisms for epoxy resin, and the behavior of secondary electrons around these materials. This study also provides a new perspective for the visualization of various forms of electron behavior around insulating materials such as epoxy resin through the control of their surface characteristics.

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Gold nanoparticles have been commonly made by a wet process from chloroauric acid or dry process using vacuum evaporation to solid surfaces. Here, we have shown a method to make gold particle from gold electrodes in potassium chloride solution by AC electrolysis and the following Turkevich method. The developed AC electrolysis method provides an environment-friendly process to produce gold particles from gold electrodes without using any strong acids such as aqua regia or hydrochloric acid.

This paper presents current research trends in advanced electron microscopy techniques for materials science. The survey is based on the special issue of Materials Transactions published in October 2019 (Vol. 60, No. 10). Advanced electron microscopy has been applied extensively to characterize various materials. The recent development and extension of analyses of electric fields and the collective motions of secondary electrons by in situ electron holography are discussed in detail.

We investigated the bonding mechanism of single-layered Cu2O nanospheres (NSs) on Cu thin films. When near-infrared femtosecond laser pulses were focused and irradiated on the Cu2O NS films containing the NSs and reducing agents on Cu thin film-coated Si substrates, single-layered NSs were bonded just above the substrates after rinsing the non-bonded NSs. The minimum pulse energy for the single bonding on the Cu thin film-coated Si substrates was smaller than that on Si substrates. The electromagnetic enhancement was calculated between the Cu2O NSs and Cu thin films by simulating the finite element method. The enhancement was estimated using a transverse mode of the linear polarization of the incident femtosecond laser pulses. The experimental and simulation results indicated that the single-layered NSs were bonded on the Cu thin films by femtosecond laser pulse-induced local heating and melting due to the localized plasmon enhancement between the Cu2O NSs and substrates.

A secondary electron (SE) energy analyzer was developed for a transmission electron microscope. The analyzer comprises a microchannel plate (MCP) for detecting electrons, a coil for collecting SEs emitted from the specimen, a tube for reducing the number of backscattered electrons incident on the MCP, and a retarding mesh for selecting the energy of SEs incident on the MCP. The detection of the SEs associated with charging phenomena around a charged specimen was attempted by performing electron holography and SE spectroscopy using the energy analyzer. The results suggest that it is possible to obtain the energy spectra of SEs using the analyzer and the charging states of a specimen by electron holography simultaneously.

We have developed the method of preparing sodium and potassium ion-selective electrodes in double-barrel glass pipettes at the size of 1 μm. Stable and precise fabrication parameters were found for producing a double-barrel 1 μm pipette, and the produced double-barrel micropipettes were used in this study. The ionophores comprising of crown ethers of 12-crown-4 for sodium ions and 15-crown-5 for potassium ions were respectively doped in poly(vinyl chloride) films in the divided double-barrel glass pipette. The obtained selectivity coefficients and selectivity ratios are compared with the previous studies. The developed ion-selective dual-micropipettes can be applied for local ion-selective measurements such as living cells.