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Nano-Fabricated Devices in Electrochemistry and Cancer Therapy
Başlık:
Nano-Fabricated Devices in Electrochemistry and Cancer Therapy
Yazar:
Wang, Yifei, author.
ISBN:
9780438066656
Yazar Ek Girişi:
Fiziksel Tanımlama:
1 electronic resource (177 pages)
Genel Not:
Source: Dissertation Abstracts International, Volume: 79-10(E), Section: B.
Advisors: Wei Wu Committee members: S.R. Narayanan; Han Wang.
Özet:
Top-down nanofabrication is a powerful tool to achieve desired nano-devices that can contribute to various types of applications. Besides the traditional semiconductor nanofabrication, an increasing attention has been focused on many other fields, e.g., nano-optics, nano-energy, nano-biomedicine, etc. Sometimes the performance of such nano-devices can be quite different from those macro-devices, and new knowledge and new functions can be generated by studying these nano-devices. In this dissertation, two top-down nanofabrication projects have been discussed.
In the first project (Chapter 1--5), we utilized deep-sub-Debye-length nanogap electrochemical cells to achieve efficient electrolysis of pure water and pure methanol solution (without any added electrolyte) at room temperature. Here we have fundamentally broken through the common knowledge that only conductive solution (or solution with strong electrolyte) can be efficiently electrolyzed. A field-assisted effect resulted from overlapped electrical double layers can greatly enhance molecules ionization and mass transport, leading to electron-transfer limited reactions. We have named this process "virtual breakdown mechanism" (which is completely different from traditional mechanisms) that couples the two half-reactions together, greatly reducing the energy losses arising from ion transport. This fundamental discovery has been theoretically discussed in this dissertation and experimentally demonstrated in a group of electrochemical cells with nanogaps between two electrodes down to 37 nm. Many efforts were put onto the improvement of fabrication yield of such deep-sub-Debye-length nanogap electrochemical cells. Based on our nanogap electrochemical cells, the electrolysis current density from pure water can be significantly larger than that from 1 mol/L sodium hydroxide solution, indicating the much better performance of pure water splitting as a potential for on-demand clean hydrogen production.
In the second project (Chapter 6--10), lithographically defined nanoparticles with high efficiency of microwave absorption have been used for cancer hyperthermia therapy. Two types of particles have been studied: resonance particles and non-resonance particles. For the LC-resonance particles, finite element method has been used for design and optimization. It was found that the limitation of the micro-resonator is not the requirement of the low resonance frequency but the low Q-value due to insufficient conductivity of natural materials. For the non-resonance particles, disk-shaped magnetic dipoles have been chosen as the high-efficiency microwave-absorbers. The fabrication and collection processes of the particles have been developed. Our measurements, based on both polymer-film nanocomposite setup and particle-suspended hydrogel setup, have demonstrated that the micro/nano-particles can absorb the external electromagnetic field efficiently and greatly enhance the localized heat generation compared to control groups without particles. Further characterization has shown that both the real and imaginary part of the permittivity of our nanocomposite have been enhanced, which is probably the fundamental reason why the microwave absorption efficiency can be improved.
In the first project, Chapter 1 discusses the state-of-art methods of industrial hydrogen generation. Chapter 2 discusses the fundamental difference between macro electrode system and nanogap electrochemical cells (taking water electrolysis as an example). Chapter 3 discusses the fabrication process of our vertical-designed nanogap electrochemical cells. Chapter 4 and 5 discusses the experiment results of pure water electrolysis and pure methanol solution electrolysis, respectively, both based on our nanogap electrochemical cells.
In the second project, Chapter 6 discusses the state-of-art methods of cancer therapy. Chapter 7 discusses the method of LC-circuit resonance particles. Chapter 8 discusses the design and fabrication of the non-resonance particles. Chapter 9 discuss the method to collect / transfer such lithographically defined particles, and uses our disk-shaped magnetic dipoles as an example to show the heating enhancement characterization. Chapter 10 further discusses the fundamental characterization of such particle/matrix nanocomposite mixtures.
Notlar:
School code: 0208
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Yer Numarası | Demirbaş Numarası | Shelf Location | Lokasyon / Statüsü / İade Tarihi |
---|---|---|---|
XX(678356.1) | 678356-1001 | Proquest E-Tez Koleksiyonu | Arıyor... |
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