Hirotoshi Furusho

Ionic Liquids of Bis(alkylethylenediamine)silver(I) Salts and the Formation of Silver(0) Nanoparticles from the Ionic Liquid System

We have prepared novel ionic liquids of bis(N-2-ethylhexylethylenediamine)silver(I) nitrate ([Ag(eth-hex-en)(2)]NO(3) and bis(N-hexylethylenediamine)silver(I) hexafluorophosphate ([Ag(hex-en)(2)]PF(6)), which have transition points at -54 and -6 degrees C, respectively. Below these transition temperatures, both the silver complexes assume amorphous states, in which the extent of the vitrification is larger for the eth-hex-en complex than for the hex-en complex. The diffusion coefficients of both the complex cations, measured between 30 (or 35) and 70 degrees C, are largely dependent on temperature; the dependence is particularly large in the case of the eth-hex-en complex cation below 40 degrees C. Small-angle X-ray scattering studies showed that the bilayer structure of the metal complex is formed in the liquid state for both the silver complexes. A direct observation of the yellowish [Ag(eth-hex-en)(2)]NO(3) liquid by transmission electron microscopy (TEM) indicates the presence of nanostructures, as a microemulsion, of less than 5 nm. Such structures were not clearly observed in the [Ag(hex-en)(2)]PF(6) liquid. Although the [Ag(eth-hex-en)(2)]NO(3) liquid is sparingly soluble in bulk water, it readily incorporates a small amount of water up to [water]/[metal complex] = 7:1. Homogeneous and uniformly sized silver(0) nanoparticles in water were created by the reduction of the [Ag(eth-hex-en)(2)]NO(3) liquid with aqueous NaBH(4), whereas silver(0) nanoparticles were not formed from the [Ag(hex-en)(2)]PF(6) liquid in the same way.

Silver nanowires with a monoclinic structure fabricated by a thermal evaporation method

Silver nanowires with a monoclinic structure (mono-Ag NWs) were fabricated by a thermal evaporation method for the first time. The crystal lattice parameters of the mono-Ag NWs were calculated using the UnitCell program. They are as follows: a = 0.303 nm, b = 1.140 nm, c = 0.292 nm, and beta = 118.5 degrees. In situ annealing experiments revealed that the as-prepared mono-Ag NWs transited to fcc-Ag NWs during annealing at approximately 1173 K for 60 s.

In situ TEM observation of decomposition of high-purity sapphire

The decomposition of α-Al2O3 under 200 keV electron irradiation has been investigated by in situ high-resolution electron microscopy (HREM). It was confirmed that aluminium precipitated from α-Al2O3 under 200 keV electron irradiation for less than 1 min over the temperature range from 700 to 1273 K. The electron dose rate was of the order of 1023 e m−2 s−1 and the vacuum level of the microscope was better than 10−6 Pa. The mechanisms of α-Al2O3 decomposition were discussed based on two possible decomposition models: the thermally activated atom movement and the forced atom displacement.

Lipid Nanotube Encapsulating Method in Low-Energy Scanning Transmission Electron Microscopy Analyses

The lipid nanotube (LNT) encapsulating method is a rational sample fixation method that can be used to mount samples for transmission electron microscopy analyses. By employing the LNT encapsulating method in 30 kV low-voltage scanning transmission electron microscopy (LV-STEM), it is possible to record multiangle images of ferritin without using the negative staining method. We have also recorded a tilted series of high-contrast LV-STEM images and reconstructed three-dimensional images. These results show that LNTs have sufficient durability for LV electron beam, and indicate the potential of the LNT encapsulating method as a sample fixation method of LV electron microscopy.

Lipid Nanotube Encapsulating Method for Two- and Three-Dimensional Transmission Electron Microscopy Analyses of Cage-Shaped Proteins

A novel, sample-fixation technique for transmission electron microscopy (TEM) is proposed. We encapsulated various samples in one-dimensional hollow cylinders of a glycolipid nanotube (LNT) and found it to be highly stable, flexible, and reproducible. The cylindrical shape of the LNT allows us to observe nanomaterials consistently even when the samples are rotated around the tube axis. This is critical in improving TEM computed tomography (CT), which suffers from the loss of the electron beam at high tilting angles because of the increased effective thickness of the supporting film. This technique makes it possible to reconstruct three-dimensional images from weak-signal TEM images. In this work, we examined two types of cage-shaped proteins, ferritin, and DNA-binding protein from starved cells (Dps). We reconstructed three-dimensional images of Fe cores from zero-loss images or from electron energy-loss spectroscopy (EELS) mapping images obtained with the Fe M2,3 edge. We also applied negative staining and vitreous ice embedding (VIE). These results show the potential of the LNT encapsulation technique.

Effects of temperature and electron energy on the electron-irradiation-induced decomposition of sapphire

The effects of temperature and electron energy on the electron-irradiation-induced decomposition of sapphire have been investigated by in situ transmission electron microscopy (TEM). It was found that the decomposition rate of α-Al2O3 increased with increasing irradiation temperature and decreased with increasing acceleration voltage. The core-hole Auger decay process (K–F model), rather than knock-on displacement, is responsible for the decomposition of α-Al2O3 under electron irradiation.

Lipid nanotube encapsulating method in low voltage scanning transmission electron microscopy

Lipid nanotube (LNT) [1] encapsulating method is an advanced sample fixation technique by encapsulating nanomaterials in homogeneous hollow cylinders of LNTs (shown in “Figure 1”). In characterizing nanomaterials with transmission electron microscopy (TEM), this method provides some advantages over usual method, in which samples are fixed on a supporting thin film.