日時：平成２１年１２月１１日（金曜日）午前１０時から１１時 30分
場所：南７号館１階学科会議室
講師：Professor Francesco Gonella (Physical chemistry Department, Venice Ca' Foscari University, Italy)
講演題目：Synchrotron radiation based X-ray absorption techniques for matter characterization
概要：
シンクロトロン放射光によるX線吸収を利用したナノ材 料のキャラクタリゼーション技術について、基礎から実際の応用までお話いただきます。
ゴネラ教授は、光機能 性ガラスの作製とキャラクタリゼーションを精力的に進められており、１１月より３ヶ月本学に滞 在しておられます。
事前に資料が欲しい方は矢野まで連絡してください。
矢野哲司（内線2523、[email protected])
日 時：2009年8月２１日（金）11:00～12:00
場 所：南７号館 １階 １０１会議室(学科会議室)
講 師：Prof. Woong Lee(Schoolof Nano & Advanced Materials Engineering,Changwon National University, Changwon, Republic of Korea)
講演題目：「Low-dimensional Systems & Their Applications」
講演内容：
In this seminar, experimental study of ZnO-based systems and the ab initio studies on carbon-aluminium systems are introduced with some major findings and achievements.
1. Preparation of ZnO-based Low-dimensional Structures and Their Device Applications
Various low-dimensional structures have been studied for their fabrications and device applications. As a two-dimensional nanostructure, Al-doped zinc oxide (ZnO:Al) films were applied to liquid crystal displays (LCDs) as transparent electrodes substituting indium tin oxide (ITO). While the ZnO:Al-based twisted nematic LCD cell showed similar operational behaviour to ITO-based counterpart, its electro-optical and residual DC characteristics were somewhat improved, which is attributed to the substantially lower density of charge carrier trapping centres in the polyimide layer/electrode interface region, demonstrating high application potential of ZnO:Al films as transparent electrodes of LCDs.
2. First Principle Study of Carbon-Aluminium Interfaces for CNT-dispersed Composites
A series of ab initio simulations were carried out for nanocomposite systems constituted of a graphene sheet and an Al (111) layer with various registries to investigate their dispersion relations, i.e. the bonding energy as a function of inter-layer distance, in combination with the electronic structures. It was predicted that the graphene/Al interface at the fundamental nano-unit level has substantially different characteristics from bulk graphite-Al systems in that its type of bonding is partially localized metallic with a cohesive energy substantially larger than that of typical bulk system graphite/Al interface. With the introduction of in-plane compressive strains in the Al (111) layer, the equilibrium interfacial bond length increased, accompanied by noticeable decrease in the cohesive energy, while the interface bonding became a weak secondary type. In summary, the predicted registry dependence of the electronic structures (or the nature of bonding) of the C-Al interface, varying between weak covalent to weak metallic, would provide some guideline for the proper choice of the material processing in the preparation of the nanocomposites with suitable interfacial strengths.
問合せ先：篠崎和夫，内線: 2518 (J.S. Cross ext. 3723, J. Cho ext. 3367)
日 時：2009年 7月 22日（水）15:00～16:00
場 所：南７号館 1階 101会議室
講 師：Prof. G. Carja (ルーマニア)
講演題目：「Toward complex nanostructures: MexOy-anionic clay matrices as self ensembles」
講演内容：
Nanoarchitectural ensembles in which different components are able to join their features and organize themselves for giving rise to materials owning complex characteristics and specific architectural features is a great interest in nowadays research. Nanoparticles of metals or metals oxides have shown a great potential for applications in nanotechnology. It was found that nanosized metals and metal oxides are not very stable in time owning an accentuate tendency to aggregate and to alter their properties from nano to microlevel. The tendency to aggregate induces nanoparticles toxicity. To reduce the nanoparticles aggregation process polymers, ligands or surfactants are used as templating or directing agents. These large compounds not only increase the cost of the obtained material but also strongly decrease and alter the accessibility of the active nanosites. The ensemble consisting of nanoparticles of metals and a biocompatible inorganic matrix can offer solutions not only to reduce the aggregation process but also to increase nanoparticles biocompatibility. The matrix is also able to bring into the cumulative structure its own characteristics thus giving rise to a tailored textural organization within micro/nanorange. Hydrotalcite – like anionic clays or more generally speaking, layered double hydroxides (LDHs), represented by the empirical formula [M(II)1-x M(III)x ∙(OH)2]x+ (An-)∙mH2O, are layered inorganic matrices able to bring into the ensembled formulation the advantage of a good biocompatibility and low cytotoxicity.
We present a facile and cheap synthesis route for obtaining new materials, as self ensembles of nanoparticles of metal or metal oxides – hydrotalcite-like clay matrices (Ag/LDH, TiO2/ZnLDH, Fe2O3/ZnLDH).
The “memory effect” of the LDH anionic clay has been “manipulated” such a way that - the reconstruction process of the clay, the formation of metal or metal oxides based nanoparticles and their deposition on the surface of the larger interconnected nanoparticles of the clay layered matrix - take place in one single step at room temperature.
Some properties of metal oxides - anionic clay matrix ensembled nanoarchitectures are also presented.
問合せ先：中島 章 内線: 2525，e-mail: [email protected]
日 時：2009年 4月 8日（水）16:00～17:00
場 所：南７号館 １階 １０１会議室(学科会議室)
講 師：Prof. Junghyun Cho (Dept. of Mechanical Engineering &
Materials Science and Engineering Program, State
University of New York (SUNY) at Binghamton, NY, U.S.A.)
* : Visiting Scholar in Ceramic Science at Tokyo Tech until
Jan. 16, 2010
講演題目：「Low-Temperature Ceramic Thin Film Processing for
Electronic Devices」
講演内容：
Ceramic thin films and coatings such as TiO2, ZrO2, SnO2, ZnO and SiO2 have
received great attention for use not only as a functional component (e.g.,
dielectrics, semiconductors, photovoltaics, sensors) but also as an
effective protective layer for metals, polymers, silicon, and biomaterials.
These films, however, suffer from inherent brittleness and easy spallation
upon mechanical and thermal stress. In addition, high-temperature
processing is normally required for achieving sufficiently dense and
crystalline structures, which limits their use in many innovative
applications. Therefore, low-temperature processing along with
damage-tolerance capability has been a key in the recent development of
ceramic film processing. Current developments in flexible electronics,
which can be portable and rollable, also require ceramic films to be
processed at low temperatures (< 100’C). In an effort to fabricate such
ceramic thin films with enhanced reliability, the solution processing
method using aqueous precursor solution was devised. It was shown that bulk
precipitation through homogeneous nucleation in supersaturated solution is
responsible for film formation, which can be controlled through various
deposition parameters (pH, temperature, concentration, electric potential).
This processing mechanism is quite similar to the formation of biominerals
such as nacre and sea urchin spine in that in-situ precipitation of
nanoparticles and proper surface functionalization of the substrate tailor
ceramic film formation and its microstructure development. In this
presentation, comprehensive characterization of the nano- and
microstructural developments of the ceramic films will be discussed with
associated properties. Construction of the generic processing map based on
better understanding of nucleation/growth mechanisms of ceramic
nanoparticles and particle interactions would offer guidance for processing
of various microstructure-adjustable ceramic films at low temperatures.
問合せ先：篠崎和夫，内線: 2518，e-mail: [email protected]