Investigation of the electromagnetic properties of single walled carbon nanotube thin films

Küçükyıldız, Şeyda
The work presented in this thesis can be divided in two parts. First part discusses the dispersion and deposition routes of single walled carbon nanotube (SWNT) thin films. Two different types of SWNTs and several dispersing agents were examined to achieve a homogeneous SWNT solution. A tip-sonicator and an ultrasonic bath was compared and it has been found that tip-sonicator increases the efficiency of SWNT dispersions. Vacuum filtration and spray coating techniques were utilized for the deposition of SWNT thin films. Optoelectronic properties of the films were examined for different SWNT densities. Moreover, SWNT thin film functionalization with acid treatment was investigated in order to improve the electrical conductivities of the thin films. Centrifugation of SWNT solutions provided higher optical transmittance at a given wavelength of 550 nm and lower sheet resistance values. It has also been found that, 150 Ω/□ sheet resistance can be achieved at an optical transmittance of 90 % for SWNT thin films on glass substrates that were deposited via vacuum filtration method. The second part investigated the electromagnetic interference shielding properties of the SWNT films. For this purpose, glass fiber woven fabrics were coated with SWNT thin films by spray coating method. Different densities of SWNT films were investigated and the electromagnetic wave reflection and transmission values were analyzed through the utilization of free-space method within a frequency range of 18 – 40 GHz. Our results indicated that the electromagnetic wave reflection properties of the samples were not satisfactory despite their conductivities within the investigated frequency range.


Synthesis characterization and modification of α-tricalcim phosphate based bone supporting systems
Çiçek, Gülçin; Hasırcı, Nesrin; Aksoy, Eda Ayşe; Department of Biomedical Engineering (2012)
The constitutive studies of this thesis were achieved and presented in three parts. In the first part, the effects of solid state synthesis process parameters and the impurity content of primary calcium precursor on the cement-type hydration efficiency for the conversion of α-tricalcium phosphate (Ca3(PO4)2 or α-TCP) into hydroxyapatite (Ca10-xHPO4(PO4)6-x(OH)2-x x = 0–1, or HAp) have been investigated (at 37°C). α-TCP was synthesized by thermal processing of stoichiometric amounts of calcium carbonate (CaC...
Efficient fpga implementation of image enhancement using video streams
Günay, Hazan; Aşkar, Murat; Department of Electrical and Electronics Engineering (2010)
This thesis is composed of three main parts; displaying an analog composite video input by via converting to digital VGA format, license plate localization on a video image and image enhancement on FPGA. Analog composite video input, either PAL or NTSC is decoded on a video decoder board; then on FPGA, video data is converted from 4:2:2 YCbCr format to RGB. To display RGB data on the screen, line doubling de-interlacing algorithm is used since it is efficient considering computational complexity and timing....
Framing the invisible : section as a spatial frame for a reconsideration of architectural representation
Alkan, Alper Semih; Savaş Sargın, Ayşen; Department of Architecture (2004)
This thesis is a critical reconsideration of the relationship of architectural production with its أmodesؤ of representation. Historically, the representation of architecture has been signifying an interval where the displacement between the mental conception and its material expression has taken place. The group composed of plan, section and elevation is called أorthographic set,ؤ which has been accepted as a universal code in architecture since it is attributed with the basic premise of its being أobjecti...
Effects of nanoadditives and different conventional flame redardants on the flammability of polystyrene
Sipahioğlu, Bengü Melike; Kaynak, Cevdet; Department of Metallurgical and Materials Engineering (2012)
In this thesis, there were four purposes. The first one was to investigate effects of nanoclays (NC) on the flammability behavior of polystyrene (PS). The second purpose was to investigate contribution of nanoclays to the flame retardancy performance of conventional phosphorus based flame retardant; triphenyl phosphate (TPP) and its synergist melamine cyanurate (MCA). For the third purpose contribution of nanoclays to the flame retardancy performance of another conventional halogenated flame retardant; brom...
Qualitative and philosophical enquiry of aikido participants from different levels, conceptualization of aikido as different from other sports : mind and body perspectives
Şentuna, Barış; Korkusuz, Feza; Department of Physical Education and Sports (2010)
This thesis is made of two main parts. First main part of the thesis is based on the qualitative enquiry of twenty-three Aikido participants from different levels - beginner, intermediate, advanced- from three different dojos. Open ended questions regarding the difference of Aikido from other sports is asked to the participants. Their written responses were coded using qualitative methods. Based on coding of documents: labels, categories and themes have been generated. Second main part of this thesis is bas...
Citation Formats
Ş. Küçükyıldız, “Investigation of the electromagnetic properties of single walled carbon nanotube thin films,” M.S. - Master of Science, Middle East Technical University, 2013.