先進国際セミナー

開催日 2017/ 7/ 21 (金)
時間帯 18:30~20:00
講師 Ipek Tuvay
(Assistant Professor of Mathematics, Mimar Sinan Fine Arts University, Turkey)
講演題目 Fusion systems and Scott modules
要旨

In the modular representation theory of finite groups there is an important notion called "a Scott module" after L.L.Scott. This is an indecomposable kG-module which has a G-stable k-basis and it has the trivial kG-module in its socle, where G is a finite group, k is an algebraically closed field of prime characteristic p, and kG is the group algebra of G over k. In this lecture we will be discussing (so-called) fusion systems and the Scott modules for kind of particular but interesting cases.


参考文献:
1. J.L.Alperin. Local representation theory. Cambridge University Press, 1986.
2. H.Nagao and Y.Tsushima. Representations of Finite Groups. Academic Press, 1989.

会場 理学部 2号館 208
開催日 2016/4/28 (木)
時間帯 16:10~17:40
講師

Carlo Requião da Cunha
(Assistant Prof. of Physics, Univ. Federal do Rio Grande do Sul - Brazil)

講演題目 Nanostructuring Oxide Semiconductors for Solar Cell Applications
要旨

According to the American Energy Information Administration (EIA), the global demand for energy is expected to grow 56 % by 2040. Nonetheless, 80 % of the world energy is expected to keep coming from fossil fuels. These are pollutant sources that not only increase an ongoing problematic global warming but are also often extracted from regions of high political instabilities. One possible candidate that can remedy this problem is the solar cell. These are semiconductor devices that use a nearly inexhaustible and green energy supply. Nevertheless, the detailed balance maximum efficiency for solar cells is limited to approximately 46 %.

In our group we have been investigating both theoretically [*1][*2] and experimentally[*3][*4] nanostructured materials that might be able to circumvent this limit with multiple carrier generation. Our main effort is on the preparation and characterization of oxide semiconductors by low-cost processes such as the low-temperature sol-gel chemistry.

In this seminar, the thermodynamics of P-N solar cells will be discussed and then some theoretical results from Monte Carlo simulations on gel structures will be shown. Our results suggest that there is a disorder threshold that separates fracton and phonon states. Moreover, the nanoparticles that compose the gel structure can be tuned to form either Zipf scale-free or Poisson networks depending on the synthesis temperature and concentration of precursors.

Experimentally, we have been synthesizing monolithic high-surface area tin oxide and tungsten trioxide aerogels by a sol-gel technique.[*3} A full characterization with SEM/TEM, BET/BJH, XRD, UV/Vis, FTIR, PL, PIXE and Thermogravimetry was performed. Our results indicate that the sol-gel synthesis inadvertently produces materials with oxygen deficiency. These defects produces a Burstein-Moss shift in oxide semiconductors, which is readily detectable by optical spectroscopy and severly changes its electrical properties.[*4]

Along this seminar all techniques will be thoroughly discussed and experimental results will be compared to theoretical models.

 

[*1] E. L. da Rocha and C. R. da Cunha, Chaos, Solitons & Fractals 44 (2011) 241.
[*2] R. V. Morales, C. R. da Cunha and C. R. Rambo, Physica A 406 (2014) 131.
[*3] C. R. da Cunha, G. H. Toffolo, C. E. I. dos Santos and R. P. Pezzi, J. Non-Cryst. Sol. 380 (2013) 48.
[*4] C. R. da Cunha, F. D. da Silva and R. Morales, MRS Proc. 1731 (2015).

会場 自然科学系総合研究棟2 マルチメディア講義室
開催日 2016/1/13 (水)
時間帯 19:30~21:00
講師 Dr. Kevin Nute
(Professor of Architecture, University of Oregon, USA)
講演題目 The Wilderness in the Metropolis
Natural Change in Urban Buildings
都市のウィルダネス
都市建築の中の自然変動
要旨

Over the past three decades the human benefits of contact with nature have been widely documented, but most building occupants do not have immediate access to natural outdoor spaces, particularly in large cities. This illustrated talk showed how the movements of the weather can be used to bring both nature and sensory stimulation to the occupants of urban buildings while also raising awareness of under-utilized sustainable practices.
自然との触れ合いによる我々への恩恵は、過去30年間にわたって立証されてきた。しかしほとんどの建物の住人、特に大都市に暮らしている人々は野外の自然空間へ直接にアクセスすることができない。その講演では、スライドを用いて、サステイナブルな自然とパッシブ活用の認識が高まる中、天気の動きがいかに自然と知覚・刺激両方を都市建築の使用者へもたらすかを明らかにしていた。

会場 工学部15号棟110番講義室
過去の先進国際セミナー