[rplgroup1] PhD Dissertation Defense - Joong Sun Park (Wed, April 20, 2:00pm, CIS-X 101)

Hee Joon Jung hjjung at stanford.edu
Mon Apr 18 10:25:37 PDT 2011


된장 하필이면 싱클레어 그룹미팅 시간이랑 완전히 겹치네...
어쨋든.. 굿럭 굿럭~~~ 뭐 당근 잘하겠쥐~~~ 교수들 좀 눌러주고 와... ㅋㅋ

희준

2011/4/18 Joong Sun Park <mrjpark at stanford.edu>

>  *
>
> Stanford University Ph.D. Dissertation Defense
> *
> *
>
>
> Title: “Nano Electrochemistry in Energy Conversion Devices”
>
> Joong Sun Park
> Department of Mechanical Engineering
> Advisor:  Prof. Fritz B. Prinz
>
> Date:  Wednesday, April 20th, 2011
> Time: 2:00 pm (Refreshments at 1:45pm)
> Location: CISX 101X (Auditorium)
> http://campus-map.stanford.edu/index.cfm?ID=04-055
>
>
> Abstract:
> *
>
> The overall efficiency of energy conversion devices such as batteries, fuel
> cells, and biological cells is often limited by charge transfer reactions at
> electrode-electrolyte interfaces. Because interfaces are the site of nearly
> all chemical (and electrochemical) reactions, understanding and improving
> their characteristics and structures can lead to significant reductions in
> both catalytic and interfacial losses. To this end, nano electrochemistry
> may offer us ways to understand details of charge transfer reaction at
> nanoscale resolution and open opportunities to engineer the interface with
> better kinetics. This talk presents in three parts the results of three
> studies aimed at lowering the electrochemical reaction losses in both
> ceramic fuel cells and biological systems.
>
> The first part of talk discusses a study of oxide ion incorporation and
> transport at the cathode of solid oxide fuel cells (SOFC). SOFCs are an
> attractive clean energy technology because of the low to zero emissions from
> their operation and their potentially high efficiency. For wider
> applications, it is desirable to lower the operation temperature of SOFCs,
> but this causes significant increase of interfacial loss due to sluggish
> kinetics of oxygen reduction reaction at the cathode. In this study, I
> demonstrated both spectroscpic (AC impedance spectroscopy) and spectrometric
> (Nano secondary ion mass spectrometry) evidence that oxygen incorporation
> from the cathode into the electrolyte is significantly enhanced at grain
> boundaries of the electrolyte.
>
> The second part of the talk discusses a study focused on proton transport
> in proton-conducting ceramic fuel cells. Acceptor-doped perovskites have
> attracted recent attention as potential electrolyte materials for the next
> generation protonic devices, including fuel cells, because of their high
> ionic conductivity at intermediate temperatures. The chemical instability of
> most of proton-conducting ceramics in acidic gas environments such as carbon
> dioxide, however, compromises their practical use. I discuss the evidence of
> proton conduction in nanoscale yttria-stabilized zirconia, well known oxide
> ion conductor; this points to its possible usage as a chemical barrier layer
> for proton-conducting ceramics.
>
> The third part of the talk presents a study of the possibility of
> extracting electricity from plant cell and the economic feasibility. Plants
> have developed sophisticated solar energy capture mechanisms that may be
> adapted to be less expensive or to perform better than current photovoltaic
> solar energy collectors. I discuss direct extraction of photosynthetic
> electrons from a single plant cell done by inserting nanoscale electrodes
> into their chloroplasts in vivo; these results may represent an initial step
> in generating “high efficiency” bioelectricity.
>
>
> Joong Sun Park
>  Ph.D. Candidate
> Mechanical Engineering
> Stanford University
>
> _______________________________________________
> rplgroup1 mailing list
> rplgroup1 at lists.stanford.edu
> https://mailman.stanford.edu/mailman/listinfo/rplgroup1
>
>


-- 
Hee Joon Jung
PhD Candidate
Robert Sinclair Group (MSE) / Fritz B. Prinz Group (ME/MSE)
Department of Materials Science and Engineering
Stanford University
Cell : 650-799-2183
Email : hjjung at stanford.edu / hjjung98 at gmail.com
Office : Durand bldg. Rm.139, 496 Lomita Mall, Stanford, CA 94305
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