Development and Application of a Sample Holder for In Situ Gaseous TEM Studies of Membrane Electrode Assemblies for Polymer Electrolyte Fuel Cells.

Polymer electrolyte fuel cells hold great potential for stationary and mobile applications due to high power density and low operating temperature. However, the structural changes during electrochemical reactions are not well understood. In this article, we detail the development of the sample holder equipped with gas injectors and electric conductors and its application to a membrane electrode assembly of a polymer electrolyte fuel cell.

Long-term biopersistence of tangled oxidized carbon nanotubes inside and outside macrophages in rat subcutaneous tissue.

Because of their mechanical strength, chemical stability, and low molecular weight, carbon nanotubes (CNTs) are attractive biological implant materials. Biomaterials are typically implanted into subcutaneous tissue or bone; however, the long-term biopersistence of CNTs in these tissues is unknown. Here, tangled oxidized multi-walled CNTs (t-ox-MWCNTs) were implanted into rat subcutaneous tissues and structural changes in the t-ox-MWCNTs located inside and outside of macrophages were studied for 2 years post-implantation.

New generation "nanohybrid supercapacitor".

To meet growing demands for electric automotive and regenerative energy storage applications, researchers all over the world have sought to increase the energy density of electrochemical capacitors. Hybridizing battery-capacitor electrodes can overcome the energy density limitation of the conventional electrochemical capacitors because they employ both the system of a battery-like (redox) and a capacitor-like (double-layer) electrode, producing a larger working voltage and capacitance. However, to balance such asymmetric systems, the rates for the redox portion must be substantially increased to the levels of double-layer process, which presents a significant challenge.

Development of a high temperature-atmospheric pressure environmental cell for high-resolution TEM.

An environmental cell for high-temperature, high-resolution transmission electron microscopy of nanomaterials in near atmospheric pressures is developed. The developed environmental cell is a side-entry type with built-in specimen-heating element and micropressure gauge. The relationship between the cell condition and the quality of the transmission electron microscopic (TEM) image and the diffraction pattern was examined experimentally and theoretically.

In-situ TEM observations of the crystallization process of solution-prepared MoS2 amorphous particles.

The crystallization of polymer-mixed amorphous molybdenum sulfide was observed in-situ by a TEM equipped with a heated specimen holder. High electron beam irradiation induced the formation of a crystal structure with a lattice spacing of 0.62 nm, which corresponds to the layer spacing of MoS2.

Development of an analytical environmental TEM system and its application.

Many automotive materials, such as catalysts and fuel cell materials, undergo significant changes in structure or properties when subjected to temperature change or the addition of a gas. For this reason, in the development of these materials, it is important to study the behavior of the material under controlled temperatures and gaseous atmospheres. Recently, a new environmental transmission electron microscope (TEM) has been developed for observation with a high resolution at high temperatures and under gaseous atmospheres, thus making it possible to analyze reaction processes in details.

Observation of three-dimensional elemental distributions of a Si device using a 360 degrees -tilt FIB and the cold field-emission STEM system.

A technique for preparation of a pillar-shaped specimen and its multidirectional observation using a combination of a scanning transmission electron microscope (STEM) and a focused ion beam (FIB) instrument has been developed. The system employs an FIB/STEM compatible holder with a specially designed tilt mechanism, which allows the specimen to be tilted through 360 degrees [T. Yaguchi, M.

Development of a specimen heating holder with an evaporator and gas injector and its application for catalyst.

A specimen heating holder equipped with a gas injector and an evaporator has been developed for use with conventional transmission electron microscopes (TEMs). The developed specimen holder allows both synthesis of metal oxide support and deposition of catalyst nano-particles in situ. Since the holder is designed to be used in small gapped high-resolution objective lens pole-piece, all the procedure from the synthesis of support material to the deposition of catalyst as well as the behavior of the catalyst nano-particles on the support can be observed at near atomic resolution.

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.

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.

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.

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).

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.

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.

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.

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.