Exploiting the chemical and physical properties of metals and minerals, it has become possible to develop new applications that improve the technical performance and to deliver greater value to businesses and consumers, and to reduce environmental burdens. In recent years the global nature of the metals and minerals market has been made very evident as many emerging economies have become significant consumers of various raw mineral products. With increasing restrictions on Chinese exports of the Rare Earths, Tungsten etc., it is very important for Japanese industries to develop secure supply options. The Japanese government has implemented to promote mineral exploration and development projects in the world, to promote technical development to reduce the recycling cost of recovering metals from used manufactured products and so on.
In order to commercialize polymer electrolyte fuel cells widely, the development of a non-Pt catalyst for oxygen reduction reaction is essentially required. In this paper, the necessity of non-Pt catalysts for low temperature fuel cells and our new trials using group 4 and 5 metal compounds are explained.
Platinum group metals (PGMs) are indispensable materials for the automotive catalyst as these metals have excellent catalytic properties. However, these metals have serious problems in terms of resource security. This is because the production amount is limited, and moreover the primary supply of the metals is restricted to the mines located in certain countries. In this article, current status of PGMs is reviewed, and recent topics on recycling technologies for recovering PGMs from the surface of the scraps are introduced.
In the Rare Metal Substitute Materials Development Project of the Ministry of Economy, Trade and Industry, dysprosium for a rare-earth magnet, indium for a transparent conducting electrode and tungsten for a cemented carbide tool are taken up, and sustained development of Japanese industry is supported. Tungsten is one of the resources unevenly distributed in China, and has and anxiety of the stable supply in the future. Tungsten is used as cemented carbide for manufacturing tools in our country. To reduce tungsten usage in the carbide tools, we are developing new technology in this project. One is development of a hybrid type-cutting tool, and another one is development of a composite structured hard material tool. In this paper, we introduce the technology for reducing tungsten usage in hard materials.
Diesel engine with high fuel efficient potential raises the expectations for reducing the carbon dioxide emission and improving an air environment. The emission gas purification absolutely requires after treatment systems such as DPF (Diesel Particulate Filter), and platinum catalysts, used for the systems, enjoy an increasing demand. From view points of both resource restriction and economical efficiency, diminishing the quantity consumed of platinum is an urgent task. Various approaches have been conducted on systems, such as microstructure control of filter, catalysts and supports.
We have performed molecular mechanics study of nanoscale peeling and adhesion processes of carbon nanotube (CNT) on the rigid graphite surface. First, as a model of CNT, single-walled carbon nanotube (SW-CNT) of the (3, 3) armchair type with a length of l = 99.3 Å comprised of 480 carbon atoms is used. In the simulation CNT physically adsorbed on the graphite substrate is peeled (retracted) from the surface and then adsorbed (approached) onto the surface. We have first obtained the vertical force-distance curve with the characteristic hysteresis loop derived from the quasistabe states between the line- and point- and non-contacts during the peeling and adhesion processes. The analysis of the vertical and lateral force curves reveals that the CNT shows multiscale mechanics — both nanoscale mechanics in the order of CNT's length (≈ 100 Å) and atomic-scale mechanics in the order of CNT's diameter (≈ several Å). The deflection of CNT along z direction and the length l dependence of kz, kz ∝ l−2.98, can be well explained by theory of elasticity. Lastly the effect of the chirarity of the CNT on the peeling and adhesion processes is studied for the armchair, zigzag and chiral type CNTs for the length of about 50 Å. The hysteresis of the peeling curve shows the adhesive behavior derived from the difference of adhesive feature and the free edge structure among different chirality of CNTs.
Electrochemical deposition of Ag on a 23×√3 reconstructed surface of Au(111) electrode at various potentials was followed by scanning tunneling microscope (STM) in situ in real time. Ag was nucleated on the faulted hcp region of the reconstruction and grew preferentially along the hcp lines (the <11-2> directions), resulted in a line shape. Formation of the Ag lines with biatomic height was more favored than that with monatomic height at more negative potentials in the range of −0.2∼+0.3 V (vs. Ag/AgCl). The growth mode of the potentiostatic electrochemical deposition of Ag on the reconstructed Au(111) electrode surface observed here is quite different from those previously reported for the electrochemical deposition on Au(111)-(1×1) electrode and deposition under ultra-high vacuum (UHV) condition on the reconstructed Au(111) surface, showing the importance both of substrate surface structure and electrode potential.
Recently graphene and negative refraction/superlens are extensively studied. Since the effective Hamiltonian describing the low-energy excitation of graphene is the same as the massless two-dimensional Dirac Hamiltonian, graphene exhibits unusual electronic properties different from those of the non-relativistic free electrons. Negative refraction has recently been realized in optics by using artificial materials called metamaterials. Negative refraction can make superlenses that have resolution beyond the diffraction limit imposed on usual lenses. After introducing briefly these two topics, this paper reviews the theoretical studies that combine them: design of graphene lenses for electrons that amplify evanescent waves and cause negative refraction.
This article describes a brief introduction to the first-principles approach with pseudo-potentials and plane-waves for a surface magnetic anisotropy. The anisotropy energies of the simple linear iron chain and the iron monolayer on platinum (001) surface are presented and are discussed.