Biomedical subjects

Takeo Kamino

Publications and source records attributed to Takeo Kamino.

8 recordsLinked to original sources

PubMed2006

Development of a gas injection/specimen heating holder for use with transmission electron microscope.

A new gas injection/specimen heating holder is developed for the purpose of in situ observation of gas reaction of materials at high temperatures in a transmission electron microscope at near-atomic resolution. A fine tungsten wire is employed as a heating element of the holder and a battery is used as the power source. Gas was injected onto specimens in the form of particles lying on the heating element via a nozzle. The maximum pressure near specimens was middle of 10(-2) Pa, while the pressure in the electron-gun chamber was kept to 2 x 10(-4) Pa. This gas injection/specimen heating holder was applied to observe solid-gas reactions. The reactions observed include oxidation of pure In into In2O3, reduction of SiO2 into Si and re-oxidation of Si into SiO2.

Journal Article↗

PubMed2006

Development of a technique for high resolution electron microscopic observation of nano-materials at elevated temperatures.

A technique for high resolution transmission electron microscopic (TEM) observation of nano-materials at very high temperatures has been developed. A spirally wound tungsten wire, normally used as the heating element of a high resolution-high temperature-specimen heating holder, was coated with a thin carbon film and the carbon film was used as the substrate of nanometer-sized specimen. The carbon film was securely self-adhered on the heater and the form of the carbon film remained unchanged until the tungsten heater is heated to around 1173 K. Temperature distribution on the carbon film has been measured by observing the sublimation of ZnS particles. Behavior of gold atoms on a surface of gold nano-particles dispersed on the carbon film has been clearly observed at 773 K in a scanning transmission electron microscope (STEM).

Journal Article↗

PubMed2005

In situ high temperature TEM observation of interaction between multi-walled carbon nanotube and in situ deposited gold nano-particles.

Interaction between multi-walled carbon nanotubes (MWNTs) and deposited gold nano-particles has been dynamically observed in a 200 kV transmission electron microscope (TEM) using a specimen heating holder. Gold particles with diameters of several tens of microns were mixed with MWNTs to mount on the heating element of a specimen heating holder. The gold particles were instantaneously heated to 1373 K to deposit gold nano-particles on the MWNTs from a very short distance. The MWNTs were then heated to 1073 K to observe interaction between the deposited gold nano-particles and MWNTs. Some gold nano-particles drilled through the wall of the MWNT and entered the capillary space of the MWNTs. To characterize the mechanism of the transition of the gold nano-particles into the capillary space of the MWNT, high resolution TEM observation of the deformed wall of MWNT was also carried out.

Journal Article↗

PubMed2004

Evaluation of TEM samples of an Mg-Al alloy prepared using FIB milling at the operating voltages of 10 kV and 40 kV.

Transmission electron microscopy (TEM) samples of an Mg-Al alloy has been prepared using a Ga-focused ion beam (FIB) milling at two different operating voltages of 10 kV and 40 kV to investigate the influence of the FIB energy on the sample quality. The fine structures of the samples have been studied using a high resolution TEM, and the concentration of the implanted Ga was analysed using an energy dispersive X-ray (EDX) analysis. The result of the TEM observation revealed that point defects were introduced to the sample finally milled at 40 kV but not at 10 kV. However, crystal lattice images and electron diffraction patterns were clearly observed on both the samples. The typical influence of the FIB energy was indicated in the elemental analysis. The relative Ga concentration in the thin sample finally milled at 10 kV was 1.0-2.0 at% that is less than half of 4.0-6.0 at% of the Ga concentration in the sample finally milled at 40 kV. A comparison between the experimental results of the Ga concentration measurement with simulation was also discussed.

Alloys↗

PubMed2004

Application of a FIB-STEM system for 3D observation of a resin-embedded yeast cell.

The combination of a focused ion beam (FIB) system and a scanning transmission electron microscope (STEM) has been applied to the three-dimensional (3D) observation of a resin-embedded yeast cell. Using a FIB microsampling technique, a sample with a thickness of tens of micrometres was extracted from a resin-embedded block sample. The extracted sample was transferred to a FIB-STEM-compatible specimen rotation holder and trimmed by FIB milling for 3D STEM observation. Although the FIB milling was carried out at an operating voltage of 40 KV, the sample was cross sectioned without forming a harmful damage layer on its surface. Cell structures, such as cell wall, cell membrane, mitochondria, peroxisomes, endoplasmic reticulum and vacuoles, were observed clearly in a pillar-shaped sample of 20 microm long, 4 microm wide and 3 microm deep.

Animals↗

PubMed2004

Improvements in performance of focused ion beam cross-sectioning: aspects of ion-sample interaction.

A gallium (Ga) focused ion beam (FIB) has been applied increasingly to 'site-specific' preparation of cross-sectional samples for transmission electron microscopy (TEM), scanning TEM, scanning electron microscopy and scanning ion microscopy. It is absolutely required for FIB cross-sectioning to prepare higher-quality samples in a shorter time without sacrificing the site specificity. The present paper clarifies the parameters that impose limitation on the following performances of the FIB cross-sectioning: milling rate, cross-sectioning at a right angle with respect to the sample surface, curtain structures formed on the cross sections, ion implantation and ion damage. All of these are discussed from the viewpoint of ion-sample interaction. Improvements for these performances achieved by diminishing their limiting origins or by correcting the resultants are described. Especially, the FIB scanning speed is significantly utilizable to improve the milling rate. A microsampling method, which allows the FIB incidence in a sidewards or upwards direction as well as downwards with respect to the microsample surface, is very effective to minimize the curtain structures.

Gallium↗

PubMed2004

A method for multidirectional TEM observation of a specific site at atomic resolution.

A new technique has been developed for the three-dimensional structure characterisation of a specific site at atomic resolution. In this technique, a focused ion beam (FIB) system is used to extract a specimen from a desired site as well as to fabricate the electron transparent specimen. A specimen holder with a specimen stage rotation mechanism has also been developed for use with both an FIB system and a high-resolution transmission electron microscope (TEM). The specimen holder allows both the FIB milling of a specimen and its observation in TEM without remounting the specimen from the specimen holder. A specimen for the three-dimensional TEM observation is extracted using the FIB micro-sampling technique and shaped into a pillar to mount on a tip of a needle stub enabling a multidirectional observation. The technique was applied to the multidirectional observation of the crystal structure of an Si single crystal at atomic resolution. The crystal lattice fringes of the two Si(111) planes with distances of 0.31 nm as well as the lattice fringes of the Si(200) with distances of 0.19 nm were clearly observed.

Imaging, Three-Dimensional↗

PubMed2001

Method for Cross-sectional Thin Specimen Preparation from a Specific Site Using a Combination of a Focused Ion Beam System and Intermediate Voltage Electron Microscope and Its Application to the Characterization of a Precipitate in a Steel.

In this study, we discuss a method for cross-sectional thin specimen preparation from a specific site using a combination of a focused ion beam (FIB) system and an intermediate voltage transmission electron microscope (TEM). A FIB-TEM compatible specimen holder was newly developed for the method. The thinning of the specimen using the FIB system and the observation of inside structure of the ion milled area in a TEM to localize a specific site were alternately carried out. The TEM fitted with both scanning transmitted electron detector and secondary electron detector enabled us to localize the specific site in a halfway milled specimen with the positional accuracy of better than 0.1 &mgr;m. The method was applied to the characterization of a precipitate in a steel. A submicron large precipitate was thinned exactly at its center for the characterization by a high-resolution electron microscopy and an elemental mapping.

Journal Article↗