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Hickerson, Anna Iwaniec Burdick Joel Wakeman. "An experimental analysis of the characteristic behaviors of an impedance pump /." Diss., Pasadena, Calif. : California Institute of Technology, 2005. http://resolver.caltech.edu/CaltechETD:etd-05232005-141405.
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Forsberg, Alexander. "Utvärdering av HyperLynx Signal Integrity genom jämförelse av simulerade och uppmätta signaler." Thesis, Tekniska Högskolan, Högskolan i Jönköping, JTH, Data- och elektroteknik, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:hj:diva-21206.
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Simulering är en viktig del av utvecklingsarbetet för nya datorkort hos Centre of Excellence - Computers på Saab AB i Jönköping. Ju tidigare i utvecklingsarbetet som defekter och svagheter hos designen hittas desto enklare och mindre kostsamma blir ändringarna att införa. På CoE används simulerings och analysverktyget HyperLynx från Mentor Graphics för att simulera alla kritiska nät. På så sätt kan svagheter hos en design hittas redan innan prototypstadiet. För att simulatorn ska vara användbar krävs dock en kunskap om hur dess resultat korrelerar med verkligheten. Det leder till den övergripande frågeställningen för detta arbete, hur väl överensstämmer HyperLynx simuleringsresultat med verkligheten? Frågeställningen besvarades genom att jämföra simuleringsresultat med motsvarande uppmätta signaler på ett testkort. Resultaten visar att HyperLynx håller en mycket god kvalitet. För signalen i helhet överensstämmer kurvformerna väl både när det gäller vilka reflektioner som bildas och timingen för reflektionerna. Enda genomgående skillnaden mellan simuleringarna och mätningarna visar på något för små amplituder för de simulerade reflektionerna.<br>Simulations are an important part of the process of designing new computer boards at the Centre of Excellence - Computers at Saab AB in Jönköping. The earlier problems and weaknesses in the design can be found during the design process the less time and money it will take to fix them. The engineers at CoE uses HyperLynx, an analysis and simulation software from Mentor Graphics, to simulate all the critical nets at the board. By doing so, the majority of the problems can be fixed before the prototyping stage. However, the engineers need to know how the simulated signals relate to real signals if the simulator is to be useful. Therefore the question to be answered in this study is how well does the simulated signals in HyperLynx imitate real signals? The question was answered by comparing simulated signals with measurements of corresponding signals on a test board. Overall the shapes of the signals are matching for both which reflections occurs and the timing of the reflections. The only noticeable difference found throughout the study is a slightly smaller amplitude of the reflections for the simulated signals compared to the corresponding measured signal. Due to these results, HyperLynx can be considered a high quality simulator.
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Puváková, Alžbeta. "Příprava a optimalizace perovskitových solárních článků." Master's thesis, Vysoké učení technické v Brně. Fakulta chemická, 2020. http://www.nusl.cz/ntk/nusl-433525.
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Perovskite solar cells are part of third generation of solar cells and thanks to their atractive properties they are potencional candidates for replacement of silicon solar cells. Inverted planar structure of perovskite solar cells is possible to prepare by low temperature methods and by solution processing techniques. Main aim of this thesis was to prepare and characterize inverted planar perovskite solr cells with a different modification of structure. Perovskite solar cells was prepared with following structures: reference perovskite solar cells, perovskite solar cells with only a perovskite layer, perovskite solar cell without electron transport and perovskite solar cell without hole transport layer. They were prepared simultaneously by spin coating. Methods used for a characterisation of a parameters of this cells were current-voltage characteristic, impedance spektroskopy, meassure of external quantum efficiency and electrolumiscence. Reference perovskite solar cell reached best results folowed by solar cell without hole transport layer. Lowest results were gained by perovskite solar cell without electron transport layer and perovskite solar cell with only perovskite layer, where increased recombination and acumulation of charge were observed,
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Holínský, Jan. "Měření pasivních kmitočtových výhybek pro reproduktorové soustavy." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2021. http://www.nusl.cz/ntk/nusl-442518.
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The content of the master´s thesis is to approach the issue of measuring the characteristics of passive frequency crossover. The work describes individual types of measured characteristics and their possibility of measurement. Then the work describes design of modules for measurement characteristics of passive frequency crossover (shunt, resistive load and amplifier). These modules were made and tested for its functions. For the amplifier is then made a second design for fulfilment requirements. The second version isn’t made in this work. At the end of the work was prepared the theoretical part of the laboratory task: Measurement of characteristics of passive frequency crossover, including protocol.
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Kermani, Behnoud. "Application of P-wave Reflection Imaging to Unknown Bridge Foundations and Comparison with Other Non-Destructive Test Methods." Master's thesis, Temple University Libraries, 2013. http://cdm16002.contentdm.oclc.org/cdm/ref/collection/p245801coll10/id/234113.
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Civil Engineering<br>M.S.C.E.<br>Proper design of bridge structures requires an appreciation for the possible failure mechanisms that can develop over the lifetime of the bridge, many of which are related to natural hazards. For example, scour is one of the most common causes of bridge failures. Scour occurs due to the erosion of soil and sediment within a channel with flowing water. During a flood event, the extent of scour can be so great that it can destabilize an existing bridge structure. In order to evaluate the scour potential of a bridge, it is necessary to have information regarding the substructure, particularly the bridge foundations. However, as of 2011 there are more than 40,000 bridges across United States with unknown foundations. Generally for these bridges there are no design or as-built plans available to show the type, depth, geometry, or materials incorporated into the foundations. Several non-destructive testing (NDT) methods have been developed to evaluate these unknown foundations. The primary objective of this research is to identify the most current and widely used NDT methods for determining the embedment depth of unknown bridge foundations and to compare these methods to an ultrasonic P-wave reflection imaging system. The ultrasonic P-wave reflection system has tremendous potential to provide more information and address several short-comings of other NDT methods. A laboratory study was initiated to explore various aspects related to the P-wave system performance, in order to characterize the limitations of the system in evaluation of unknown foundations prior to deployment in field studies. Moreover, field testing was performed using the P-wave system and a number of the current NDT methods at two selected bridge foundations to allow comparison between the results.<br>Temple University--Theses
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Guzej, Michal. "Rotující odtržení v prostoru odstředivého kompresoru." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2012. http://www.nusl.cz/ntk/nusl-230025.
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This thesis deals with a procedure for determining the complete processing of aerodynamic flow instabilities (rotating stall and surge) in a centrifugal compressor. At small flows the performance of a compressor system is limited by the surge line, which is caused by flow instabilities. Numerical solution is obtained using the method of transfer matrix. This system is simulated through several models with local resistances that represent the dissipation of pressure energy. Pulses are excitated in these models by the pressure jump placed before the centrifugal compressor. From the frequency-amplitude characteristics for the selected range of frequencies and flow the impedance characteristic of the compressor system is determined. We are looking for problematic frequencies in this characteristic that cause flow instabilities in the compressor system.
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Rezaei, Niya Seyed Mohammad. "Process modeling of impedance characteristics of proton exchange membrane fuel cells." Thesis, University of British Columbia, 2015. http://hdl.handle.net/2429/53653.
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The impedance characteristics of proton exchange membrane (PEM) fuel cells are studied and analyzed in this thesis. The modeling approaches presented in literature are thoroughly reviewed and categorized as the measurement-modeling and process-modeling approaches. In the former category, a hypothetical equivalent circuit which has the impedance characteristics similar to measured impedances is presented. Since the equivalent circuit is not directly resulted from the physical and chemical properties of the PEM fuel cells, the majority of the measurement-modeling approaches lead to dubious conclusions. In the process-modeling approach, on the other hand, the governing equations of the fuel cell must analytically be solved to determine and the impedance. However, a few process-modeling approaches presented in literature have shown to be indirectly based on the same assumptions as the measurement-modeling approach, and hence, those can also lead to similar conclusions. Therefore, these process-modeling approaches are referred to as the semi-process models here.
In this thesis, the first complete process model for PEM fuel cells is presented which is not based on the above-mentioned assumptions. For each source of the losses in the fuel cell (i.e., the ohmic, activation and concentration overpotentials), a process model and equivalent circuit are obtained and compared against the impedance measurements reported in literature. The complete model (obtained by combining the models of the three losses) is then verified against the impedances measured in different operating conditions. Using the verified model, the measured Nyquist plots of the PEM fuel cells reported in literature are categorized. As a result, the dominant physical and chemical parameters controlling various arcs of the Nyquist plot are determined. Finally, the sensitivity analysis of the impedance characteristics of fuel cells is conducted using the verified model. As a result of this analysis, a minimum change in the operating conditions which results in statistically different Nyquist plots are determined.
Finally, as an application of the model presented here, the impedance of the cell in the anode and cathode starvation modes are studied. It is shown that the anode starvation cannot be recognized from the impedance measurements, as predicted by the model.<br>Applied Science, Faculty of<br>Engineering, School of (Okanagan)<br>Graduate
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Villamil, Susan Simmons. "Impedance characteristics and grain boundary effects in titanate-based multilayer ceramic capacitors." Thesis, Virginia Polytechnic Institute and State University, 1987. http://hdl.handle.net/10919/94507.
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The major goal of this study was to gain a better understanding of the effects that grain boundaries have on conduction in multilayer ceramic (MLC) capacitors. Electrical measurements were made so that current-voltage curves and impedance plots could be constructed.
It was found that the current-voltage curves of new COG and X7R multilayer ceramic capacitors are both ohmic at low voltages and super-ohmic at intermediate voltages. Ohmic behavior prevails at high voltages for both types. Such behavior can be attributed to grain boundaries.
Grain boundary resistance was clearly exhibited by X7R-type density blanks and one commercially manufactured type of X7R MLC capacitor, while the NPO density blank and two different values of Z5U multilayer ceramic capacitors, each from a different manufacturer, indicated the possibility of grain boundary resistance. All of the samples that were tested showed possible, if not probable, evidence of grain resistance. Only the Z5U-type density blank showed a resistance contribution from the bulk-electrode interfaces.
A model for the grain boundary potential barrier height was developed. It was found that barrier height reduction occurs for small grain sizes due to depletion of the grain, and for increased grain curvature. Dopant effects are also responsible for barrier height reduction.
These results, and the related modelling, indicate that grain boundary contributions to titanate-based ceramic resistance can vary widely from sample to sample, since there are so many material dependent variables involved. Such measurements as those described here can help clarify how grain boundaries and other factors contribute to ceramic resistance.<br>M.S.
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Habtemariam, Filmon A. "HIGH-FREQUENCY IMPEDANCE CHARACTERISTICS AND HEALTH CONDITION MONITORING OF OVERHEAD POWER LINES." University of Akron / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=akron1472735633.
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Lee, Iljae. "Acoustic characteristics of perforated dissipative and hybrid silencers." Connect to resource, 2005. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1117631229.
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Thesis (Ph. D.)--Ohio State University, 2005.<br>Title from first page of PDF file. Document formatted into pages; contains xvi, 195 p.; also includes graphics. Includes bibliographical references (p. 183-195). Available online via OhioLINK's ETD Center
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Hänninen, Seppo. "Single phase earth faults in high impedance grounded networks : characteristics, indication and location /." Espoo [Finland] : Technical Research Centre of Finland, 2001. http://www.vtt.fi/inf/pdf/publications/2001/P453.pdf.
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Okazaki, Tomohisa. "Characteristics of Electrical Anisotropy in Magnetotelluric Responses." Kyoto University, 2018. http://hdl.handle.net/2433/232256.
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Maxted, Katsuo J. "Experimental Investigation on Acoustic Characteristics of Convergent Orifices in Bias Flow." University of Cincinnati / OhioLINK, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1439304400.
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Çelebi, Hasan Basri. "Noise and Multipath Characteristics of Power Line Communication Channels." Scholar Commons, 2010. https://scholarcommons.usf.edu/etd/1594.
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With the recent developments in technology, information and communication technologies (ICTs) are becoming more widespread and one of the basic building blocks of every humans life. The increasing demand in broadband communication calls for new technologies. Power line communication (PLC) is one of the potential candidates for next generation ICTs. Although communication through power lines has been investigated for a long time, PLC systems were never taken into account seriously because of its harsh communication medium. However, with the development of more robust data transmission schemes, communication over the power lines is becoming a strong alternative technology because of the existence of the infrastructure and the ubiquity of the network.
In order to establish reliable communication systems operating on power line networks (PLNs), characteristics of power line channels have to be investigated very carefully. Unpredictable characteristics of PLNs seriously affect the performance of communication systems. Similar to the other communication channels, PLC environment is affected by noise, attenuation, and multipath type of channel distortions. The level of noise in PLNs is much higher than any other type of communication networks. Furthermore, the frequency dependent attenuation characteristics of power lines and multipath stemming from impedance mismatches are the other distortion factors which have to be investigated in order to establish a reliable PLC system.
In this thesis, we focus on modeling of noise, frequency dependent attenuation, and multipath characteristics of power line channels within the frequency range between 30kHz and 30MHz.
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Steininger, Gavin Arthur Mervyn Wyverstone. "Determination of the acoustical diffusion and impedance characteristics of surfaces by Bayesian inversion of a modified Helmholtz equation." Thesis, University of British Columbia, 2009. http://hdl.handle.net/2429/11995.
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A surface diffusion coefficient is used in architectural-acoustics to evaluate the effectiveness of diffusing surfaces. The inclusion of the diffusion characteristics is also important for the accuracy of room prediction models. Another important parameter is the absorption or impedance of a surface. In settings with significant low-frequency noise, phase effects are important; consequently impedance values of surfaces are necessary for accurate modeling. A review of existing models for specular and diffuse reflection is made. A new diffusion coefficient is defined and included in three new forward models for predicting the steady-state sound-pressure level above a finite-impedance plane in an otherwise free field. Data are collected for several typical architectural surfaces in an anechoic chamber. Inverse methods are utilized in order to estimate the diffusion coefficient for surfaces given each of the models. This is done without knowledge of the surface impedance, which is simultaneously estimated. The models are compared with each other and with independently measured values of the surface impedance and diffusion. Inversion is found to be a reasonable way of determining the diffusion properties of a surface.
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Zhang, Yitian. "STUDIES TO IMPROVE EXHAUST SYSTEM ACOUSTIC PERFORMANCE BY DETERMINATION AND ASSESSMENT OF THE SOURCE CHARACTERISTICS AND IMPEDANCE OPTIMIZATION." UKnowledge, 2016. http://uknowledge.uky.edu/me_etds/77.
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It is shown that the relationship between an impedance change and the dynamic response of a linear system is in the form of the Moebius transformation. The Moebius transformation is a conformal complex transformation that maps straight lines and circles in one complex plane into straight lines and circles in another complex plane. The center and radius of the mapped circle can be predicted provided that all the complex coefficients are known. This feature enables rapid determination of the optimal impedance change to achieve desired performance.
This dissertation is primarily focused on the application of the Moebius transformation to enhance vibro-acoustic performance of exhaust systems and expedite the assessment due to modifications. It is shown that an optimal acoustic impedance change can be made to improve both structural and acoustic performance, without increasing the overall dimension and mass of the exhaust system. Application examples include mufflers and enclosures. In addition, it is demonstrated that the approach can be used to assess vibration isolators. In many instances, the source properties (source strength and source impedance) will also greatly influence exhaust system performance through sound reflections and resonances. Thus it is of interest to acoustically characterize the sources and assess the sensitivity of performance towards source impedance. In this dissertation, the experimental characterization of source properties is demonstrated for a diesel engine. Moreover, the same approach can be utilized to characterize other sources like refrigeration systems. It is also shown that the range of variation of performance can be effectively determined given the range of source impedance using the Moebius transformation.
This optimization approach is first applied on conventional single-inlet single-outlet exhaust systems and is later applied to multi-inlet multi-outlet (MIMO) systems as well, with proper adjustment. The analytic model for MIMO systems is explained in details and validated experimentally. The sensitivity of MIMO system performance due to source properties is also investigated using the Moebius transformation.
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Tamilselvan, Karthi. "The Impacts of Ultra High Voltage AC line characteristics on line distance protection." Thesis, KTH, Skolan för elektro- och systemteknik (EES), 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-194315.
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With the growing load demand, Ultra high Voltage (UHV) transmission lines are utilized in many countries around the world for bulk power transmission from remote locations over long distance. UHV transmission lines have typical features and it poses a challenge to the power system design with respect to protection, insulation and reactive power compensation, etc. Protection is a key issue in UHV transmission since a relay failure can interrupt and damage the power system. There are distance and differential protection schemes in the transmission line which account for security of the power system. This thesis report is based on analysis carried out to find out the typical features associated with the UHV transmission systems. Also the impacts of the UHV transmission line characteristics on line distance protection scheme are observed. The traditional distance relays based on the lumped line parameters are not suited for the UHV transmission lines of very long distances. In this case a simulation is carried out for a 765 kV transmission system modeled in PSCAD. In such a case the non-linearity is even more prominent and the relay is less dependable. In line with the simulation and the analysis for the challenges in UHV transmission system, it is observed that the fault impedance of the line is non-linear and this non-linearity causes the failure of relay operation for a fault location at the boundary of the zone of protection. The fault simulation was carried out in PSCAD and the quadrilateral distance relay characteristics were plotted using MATLAB. From the simulation and results, it is finally concluded that traditional distance protection relays with lumped parameter line modeling is not suitable for UHV transmission liens due to non-linearity in fault impedance and it leads to relay failure.<br>Ultra high voltage (UHV) transmissionsledningar används i många länder till följd av ett växande behov av överföra hög effekt från avlägset belägna produktionsanläggningar till konsumenter. UHV-transmissionsledningar har speciella egenskaper som innebär utmaningar vid designandet av kraftsystem. Några utmaningar är systemskydd, isolation, och reaktiv effektkompensering. Systemskydd är en viktig aspekt för UHV-transmission eftersom haveri av reläskydd kan orsaka driftstopp och även skada ett kraftsystem. Det finns distans- och differentialskydd i transmissionsledningar som utgör skydd för kraftsystemet. Denna avhandling är baserad på analyser som har utförts för att åskådliggöra de typiska egenskaperna som är sammankopplade med UHV-transmissionssystem. Även inverkan på distansskydd orsakad av karaktäristiken av UHV-transmissionsledningar utvärderas. De traditionella distansreläskydden som baseras på de sammanslagna ledningsparametrarna är inte lämpade för UHV-transmissionsledningar som stäcker sig över långa avstånd. I detta fall har en simulering utförts i PSCAD för ett transmissionssystem med spänningen 765 kV. I ett sådant fall är karaktäristiken ännu mer olinjär och reläskydden ännu mindre pålitliga. Det observeras att felimpedansen för ledningen är olinjär och till följd av detta orsakas problem med reläskydden då ett fel uppkommer vid utkanten av den skyddade zonen. Denna observation överensstämmer med simuleringarna och de förväntade utmaningarna kopplade till UHV. Simuleringar av felfall utfördes i PSCAD och karaktäristiken av reläskydden plottades med hjälp av MATLAB. Från resultat presenteras i rapporten, konkluderas det att konventionella distansskyddsreläer med modellering av sammanslagna ledningsparametrar inte är lämpliga för UHV-transmissionsledningar på grund av att den olinjära felimpedansen leder till att reläskydden havererar.
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Shen, Boyang. "Study of second generation high temperature superconductors : electromagnetic characteristics and AC loss analysis." Thesis, University of Cambridge, 2018. https://www.repository.cam.ac.uk/handle/1810/276688.
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This thesis presents a novel study on Second Generation High Temperature Superconductors, which covers their electromagnetic characteristics and AC loss analysis. Lorentz Force Electrical Impedance Tomography (LFEIT) is one of the most promising hybrid diagnostic scanners with burgeoning potential for biological imaging, particularly in the detection of cancer and internal haemorrhages. The author tried a novel combination of superconducting magnets together with the LFEIT system. The reason is that superconducting magnets can generate a magnetic field with high intensity and homogeneity, which could significantly enhance the electrical signal induced from a sample, thus improving the Signal-to-Noise Ratio (SNR). The author developed four magnet designs for the LEFIT system using the Finite Element Method (FEM) package, COMSOL Multiphysics, and found that a Superconducting Halbach Array magnet can achieve all the requirements (magnetic field properties, geometry, portability, etc.) for the LFEIT system. The optimization study of the superconducting Halbach Array magnet has been carried out on the FEM platform of COMSOL Multiphysics, with 2D models using H-formulation based on B-dependent critical current density and bulk approximation. Optimization focused on the location of the coils, as well as the geometry and number of coils on the premise of maintaining the total amount of superconducting material used in the design. The optimization results showed that the Halbach Array configuration based superconducting magnet is able to generate a magnetic field with an intensity of over 1 Tesla and improved homogeneity. In order to efficiently predict the optimization performance, mathematical formulas were developed for these optimization parameters to determine the intensity and homogeneity of the magnetic field. The mathematical model for the LFEIT system was built based on the theory of the magneto-acousto-electric effect. Then the basic imaging of the electrical signal was developed using Matlab. The magnetic field properties of the magnet design were imported into the LFEIT model. The LFEIT model simulated two samples located in three different magnetic fields with varying magnetic strength and homogeneity. Even if there are no actual alternating currents involved in the DC superconducting magnets mentioned above, they have power dissipation during normal operation (e.g. magnet ramping) and under different background fields. This problem generally goes under the category of “AC loss”. Therefore, the AC loss characteristics of HTS tapes and coils are still fundamentally important for HTS magnet designs, even if they are normally operating in DC conditions. This thesis starts with the AC loss study of HTS tapes. The investigation and comparison of AC losses on Surround Copper Stabilizer (SCS) Tape and Stabilizer-free (SF) Tape have been carried out, which includes AC loss measurement using the electrical method, as well as the real geometry and multi-layer HTS tape simulation using the 2D H formulation by COMSOL Multiphysics. Hysteresis AC losses in the superconducting layer, and eddy current AC losses in the copper stabilizer, silver overlayer and substrate were concerned in this investigation. The measured AC losses were compared to the AC losses from the simulation, using 3 cases of different AC frequency: 10 Hz, 100 Hz, and 1000 Hz. The frequency dependence of AC losses from Stabilizer free Tape and Copper Stabilizer Tape were compared and analysed. A comprehensive AC loss study of a circular HTS coil has been fulfilled. The AC losses from a circular double pancake coil were measured using the electrical method. A 2D axisymmetric H-formulation model using FEM package COMSOL has been established, which was able to make consistency with the real circular coil used in the experiment. To model a circular HTS coil, a 2D axisymmetric model provided better accuracy than a general 2D model, and was also more efficient than a 3D model. Three scenarios were analysed: (1) AC transport current and DC magnetic field, (2) DC transport current and AC magnetic field, (3) AC transport current and AC magnetic field. The angular dependence analysis on the coil under the magnetic field with the different orientation angle was carried out for all three scenarios. For scenario (3), the effect of the relative phase difference ∆ between the AC current and the AC field on the total AC loss of the coil was investigated. To summarise, a current/field/angle/phase dependent AC loss (I, B, , ∆) study of circular HTS coil has been carried out, which could potentially benefit the future design and research of HTS AC systems. The AC losses of horizontally parallel HTS tapes have been investigated. The AC losses of the middle and end tape of three parallel tapes have been measured using the electrical method, and compared to those of an individual isolated tape. The effect of the interaction between tapes on AC losses has been analysed, and compared with finite element method (FEM) simulations using the 2D H formulation implemented in COMSOL Multiphysics. The electromagnetic induction around the three parallel tapes was monitored using COMSOL simulation. The electromagnetic induction and AC losses generated by a conventional three turn coil were simulated as well, and then compared to the case of three parallel tapes with the same AC transport current. The analysis demonstrated that HTS parallel tapes could be potentially used in wireless power transfer systems, which could have lower total AC losses than conventional HTS coils. By using FEM simulations, cases of increasing number of parallel tapes was considered, and the normalised ratio between the total average AC losses per tape and the AC losses of an individual single tape have been calculated for different gap distances. A new parameter is proposed, Ns, a turning point the for number of tapes, to divide Stage 1 and Stage 2 for the AC loss study of horizontally parallel tapes. For Stage 1, N < Ns, the total average losses per tape increased with the increasing number of tapes. For Stage 2, N > Ns, the total average losses per tape started to decrease with the increasing number of tapes. The analysis demonstrates that horizontally parallel HTS tapes could be potentially used in superconducting devices like HTS transformers, which could retain or even reduce the total average AC losses per tape with large numbers of parallel tapes.
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Marek, Pavel. "Měření přenosových a imitančních charakteristik aktivních obvodových prvků." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2009. http://www.nusl.cz/ntk/nusl-218000.
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This diploma work deals with active circuit elements and proposals of methods for measuring of some parameters of these elements. In the opening part the work deals with general classification of elements used in electronic circuits, ideal and real current sources and power supplies. Further there are stated basic parameters and characteristics presented by producers in a catalogue sheet for active elements MAX435, OPA660, AD844 and MAA741 element which already belongs to the history of IC. Main attention is paid to active circuit elements with current sources driven by CCCS (Current Controlled Current Source) and AD844 (high speed monolithic operational amplifier). In the work there is described a method for determining of selected parameters of active elements with CCCS. Examined parameters were frequency characteristics of current transfer, input impedance and output impedance. The proposed method was verified by a computer simulation on above mentioned active elements by means of PSpice software. Findings along with the description are summarized at the end of the work. In the closing part of the work there is undertaken a real measure of AD844 element based on the proposed method and the findings are compared with particular simulations. However, at first a flat connection board was made by means of EAGLE software and then the measure was performed on it.
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Mlčkovová, Hana. "Studium dielektrických vlastností krystalů perovskitů." Master's thesis, Vysoké učení technické v Brně. Fakulta chemická, 2021. http://www.nusl.cz/ntk/nusl-445134.
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The presented diploma thesis deals with the preparation of perovskite single crystals by inverse thermal crystallization and subsequent study of the basic properties of these hybrid organic-inorganic materials that can be used in various optoelectronic (photodetectors, transistors, lasers, LEDs) or photovoltaic applications. Their behavior in the electric field was studied by impedance spectroscopy. Impedance and capacitance-voltage (C-V) characteristics (frequency dependences) were measured in the dark and in the light. From the impedance dependences for measurements at 0 V voltage in the dark, the equivalent circuit was modeled and its parameters and dielectric constant were determined. From the C-V dependence, Mott-Schottky analysis determined the parameters – "flat-band" potential U_"fb" and charge carrier density N_"C-V" , the parameter – the so-called Warburg coefficient was found, which together with the parameter N_"C-V" was used to calculate the diffusion coefficient D.
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Mancl, Vlastimil. "Systém Hefaistos." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2019. http://www.nusl.cz/ntk/nusl-400640.
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This master's thesis describes functionality and principle of the Hefaistos measurement system, which is fully automated and modular. Its purpose is to measure frequency responses of materials and its temperature dependence. The thesis describes all the necessary parts of the modular measurement system. Main part of this system is the control application programmed in LabVIEW software environment. Another necessary parts are impedance analyzers for acquiring frequency dependencies and heating chambers for heating measured materials. The control application ensures hardware synchronization between impedance analyzers and heating chambers. Together they create the Hefaistos system. Modularity of the system means that a user may choose which instrument combination will be used. The system offers choice between three impedance analyzers Agilent 4294A, Wayne Kerr 6520B and HIOKI 3532 LCR Hi-Tester and two heating chambers AOIP GEMINI 700 LRI and AOIP HYPERION. Possibilities of the Hefaistos system are demonstrated on the results of an example measurement.
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Maráčková, Lucie. "Studium elektrických a dielektrických vlastností plynových senzorů na bázi iontových kapalin." Master's thesis, Vysoké učení technické v Brně. Fakulta chemická, 2017. http://www.nusl.cz/ntk/nusl-316154.
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This diploma´s thesis is focused on a study of electrical and dielectric properties of gas sensors based on ionic liquids. Measurements were done on two different types of OECT substrates (0099 and 0160). Three ionic liquids and physiological solution PBS were chosen as electrolytes. Direct current current-voltage characteristic was measured. Switching rations of transistors with this electrolyte were determined by current-voltage characteristic. Alternating resistivity dependence on frequency were measured as well. Better properties showed OECT 0099 substrates.
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Al, Mahmud Shamsul Arefeen. "Wireless Power Transfer : Machine Learning Assisted Characteristics Prediction for Effective Wireless Power Transfer Systems." Thesis, KTH, Skolan för elektroteknik och datavetenskap (EECS), 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-286673.
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One of the main challenges in wireless power transfer (WPT) devices is performance degradation when the receiver’s position and characteristics vary. The variations in the system parameters such as load impedance and coupling strength in WPT devices affect performance characteristics such as output voltage and power. When the system parameters are different from the optimal operating conditions, the performances are degraded. Therefore, the load impedance and coupling strength must be monitored to do the necessary optimization and control. However, such control approaches require additional sensing circuits and a data communication link between transmitter- and receiver-sides. This study proposes a new machine learning (ML) assisted WPT system that predicts the power delivered to the receiver by only using measurements at the transmitter-side. In addition, a method is also proposed to estimate load impedance and coupling coefficient using machine learning approach. We study what parameters measurable at the transmitter-side can be used to predict the output power delivered to receivers at variable load impedance and coupling strengths. In the proposed method, the output power of an inductor-capacitor-capacitor (LCC)-Series tuned WPT system is successfully predicted only using the measured root-mean-square (RMS) of the input current. Random forest algorithm has shown best accuracy to estimate the output power based on transmitter-side parameters only. The proposed approach is experimentally validated using a laboratory prototype. Harmonic components of the input current are used to assess the load impedance and coupling coefficient successfully. Multi-output regression has the highest accuracy for estimating the load impedance and coupling coefficient. The proposed ML algorithm is also used to classify the turn-on and -off regimes to ensure high-efficient operation.<br>En av de viktigaste utmaningarna med trådlösa kraftöverföring enheter är degraderingen av prestandan när mottagarens position och egenskaper varierar. Variationerna av systemets parametrar, såsom belastningsmotstånd och kopplings styrka i WPT-anordning, påverkar prestanda egenskaperna såsom spänning och effekt. När system parametrarna skiljer sig från de optimala drifts förhållandena, försämras prestandan. Därför måste luftmotståndet och kopplings styrkan övervakas, för att göra nödvändig optimering och kontroll. Sådana styrmetoder kräver emellertid ytterligare avkännings kretsar, och en data kommunikationslänk mellan sändar- och mottagarsidan. Denna studie föreslår ett nytt maskininlärning assisterat WPT-system, som förutsäger kraften som levereras till mottagaren genom att endast använda mätningar på sändarsidan. Dessutom föreslås en metod för att detektera belastningsimpedans och kopplings koefficient med användning av maskin inlärningsmetoder. Vi studerar vilka parametrar som är mätbara på sändarsidan och som kan användas för att förutsäga utgången effekten som levereras till mottagare vid varierande belastningsmotstånd och kopplings nivåer. I den föreslagna metoden förutses framgångs effekten för ett induktor-kondensator-kondensator LCCserie avstämt WPT-system endast framgångsrikt med hjälp av det uppmätta effektivvärdet för ingångs strömmen. Slumpmässig skogsalgoritm har visat exceptionell noggrannhet för att uppskatta uteffekten endast baserat på sändarsidans parametrar. Den föreslagna metoden valideras experimentellt med användning av en laboratorium prototyp. Harmoniska komponenter i ingångs strömmen används för att framgångsrikt bedöma last motståndet och kopplings koefficienten. Multi-utgångsregression har verkat vara mycket exakt för att uppskatta belastningsimpedans och kopplingskoefficient. Den föreslagna maskininlärning algoritmen används också för att klassificera start-och-off-regimer för att säkerställa hög effektiv drift.
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Pospíšil, Jan. "Studium dielektrických vlastností struktur tenkých vrstev organických materiálů." Doctoral thesis, Vysoké učení technické v Brně. Fakulta chemická, 2016. http://www.nusl.cz/ntk/nusl-261290.
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The dissertation is focused on the study of electric and especially dielectric properties of thin film organic materials with their huge potential for optoelectronics and other industrial sectors. The theoretical part deals with the use of organic materials in organic photovoltaic cells, the methods of deposition techniques and characterization. The theoretical knowledge of the dielectric spectroscopy, including methods for determining the physical properties and evaluation of experimental data are also described. The experimental part is devoted to the study of small molecule organic solar cells with bulk heterojunction composed of electron donor molecule of DPP(TBFu)2 and electron acceptor fullerene derivatives, such as PC60BM, PC70BM and TC60BM. The experimental part is divided into two main parts. The first part deals with the study of processes occurring at the interface between the active layer and the contact; the second part is focused on transport processes inside the structure of photovoltaic cells and also contains a study of perovskite solar cells.
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Mitáčková, Martina. "Studium vlastností tranzistorů s iontovými kapalinami." Master's thesis, Vysoké učení technické v Brně. Fakulta chemická, 2021. http://www.nusl.cz/ntk/nusl-449404.
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This diploma thesis is focused on the study of electric and dielectric properties of transistors based on ionic liquids. The measurements were performed on organic electrochemical transistors with a semiconducting channel made of PEDOT:PSS, which were firstly prepared on ITO substrates, later they were printed using 3D print. Ionic liquid NO4 (1-butyl-3-methylimidazolium hydrogensulfate) was used for measuring of the properties. Electrical properties were determined by measuring volt-ampere characteristics, dielectric properties were measured by impedance spectroscopy.
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Dirbák, Štefan. "Návrh a realizace plošného měření rezistivity půdy." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2020. http://www.nusl.cz/ntk/nusl-413053.
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This diploma thesis deals with research and study of soil impedance measurement and soil resistivity. Currently, the issue of measuring and determining soil resistance is ensured through the gradual measurement of certain soil parameters at individual points of the surface (or depth of the ground). This thesis focuses on the idea of measuring soil resistance on a certain area using a network of electrodes through a suitably designed test, measurement and evaluation system. Such an approach may find application in the need to determine soil parameters (such as resistivity) on a specific demarcated area (or depth). The prospect of such an application can be seen in saving time, energy and money needed to measure the soil resistivity of a certain area (as opposed to gradual point measurements). The configuration possibilities of OMICRON CPC 100 measuring instrument were used for the design and implementation of the measuring system for the mentioned purpose. The work is completed by verification of the proposed solution by real measurement with evaluation of the results.
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Ravel, Guillaume. "Conception et caractérisation d'une décharge capacitive à 13,56 MHz utilisant une cathode à champ magnétique dynamique intégré pour la gravure sèche des microcircuits." Grenoble 1, 1987. http://www.theses.fr/1987GRE10135.
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Ce memoire decrit la mise en oeuvre, l'etude et la caracterisation d'un reacteur de gravure seche pour le traitement de substrats en microelectronique. Apres une analyse tres schematique des parametres d'une action de gravure et des influences respectives sur ces parametres de diverses structures de decharge, nous avons developpe un dispositif experimental utilisant deux electrodes excitees en radiofrequence et un champ magnetique externe. Une phase d'evaluation sur des gravures de silicium polycristallin en plasma de sf::(6) nous a conduit a un reacteur prototype dote d'une cathode originale a champ magnetique dynamique integre. Les caracteristiques de ce reacteur dans deux modes de fonctionnement ont ete etudies par une methode optique de spectrometrie d'emission et une methode nouvelle de mesures d'impedance de decharges en radiofrequence. Des gains importants ont ete observes sur les caracteristiques de fonctionnement en sf::(6) et cl::(2) (vitesse de gravure, densites de courant d'ions) par l'application du champ magnetique sur la decharge
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Florián, Pavel. "Studium elektrických a dielektrických vlastností alkalicky aktivovaných aluminosilikátů se zvýšenou elektrickou vodivostí." Doctoral thesis, Vysoké učení technické v Brně. Fakulta chemická, 2019. http://www.nusl.cz/ntk/nusl-393991.
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This dissertation deals with the study of electric and dielectric properties of composite structures on the base of alkali-activated aluminosilicates with admixtures of various carbon particles. These materials fabricated from alkali-activated blast furnace slag, quarz sand, natrium water glass as alkali activator, water, dispersant and small amount of carbon admixture (carbon black, graphite powder, carbon fibers or carbon nanotubes) to increase electric conductivity may be used for example to construction of snow-melting, deicing and self-monitoring systems. Their current-voltage characteristics and impedance spectra were used for determination of electric and dielectric properties of these structures. The equivalent circuits were used for evaluation of impedance spectra. The results were correlated with thermal properties of these structures.
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Pospíšil, Jan. "Studium optoelektrických vlastností tenkých vrstev organických polovodičů." Master's thesis, Vysoké učení technické v Brně. Fakulta chemická, 2012. http://www.nusl.cz/ntk/nusl-216901.
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The thesis is focused on the study of electric and dielectric properties of thin film organic materials that can be used as an active layer of photovoltaic cells. Primarily were studied the properties of the layers on the glass substrates, which consist of a thin active layer of phthalocyanines. On the samples were first measured current-voltage characteristics (in the dark and during the exposure) and the basic parameters of the photovoltaic conversion were determined. Finally were measured frequency dependencies (impedance spectra, in the dark and during the exposure) and the parameters of a model of the structure with organic semiconductor were determined. The obtained results will be used to optimize the properties of photovoltaic cells.
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Miklíková, Zdeňka. "Studium optoelektrických vlastností tenkých vrstev organických polovodičů na bázi ftalocyaninů." Master's thesis, Vysoké učení technické v Brně. Fakulta chemická, 2015. http://www.nusl.cz/ntk/nusl-217103.
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Diploma thesis is focused on the study of optoelectric properties of thin layers of organic materials based on phthalocyanines, which can be used as an active layer of photovoltaic cells. Especially are studied the properties of the thin active layers of PdPc and PdPc + IL on the glass or ceramic substrates with aluminium contact, which are prepared by material printing here. On the prepared samples were first measured current-voltage characteristics in the dark and in the light and then were measured impedance spectrums in the dark. The received results will be used to improve the properties and structures of photovoltaic cells.
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Wang, Wen-Ping, and 王文萍. "Coupled-Line Coupler with Impedance Transforming Characteristic." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/33k6zw.
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碩士<br>國立交通大學<br>電信工程研究所<br>106<br>In this thesis, coupled-line coupler with impedance transforming characteristics is proposed using quarter-wavelength transformer and coupled-line coupler. It is a planar circuit consisted of microstrip lines and coupled line with enhanced coupling structures, which makes it simple to manufacture and reliable.
In order to generalize the concept with broadband impedance transforming characteristics, two coupled-line couplers with different constructure are designed and measured. The proposed coupled-line couplers, with center frequency 1.5GHz,input impedance 50 Ohm and output impedance 20 Ohm, are manufactured on a Rogers RO4003 substrate with dielectric constant of 3.55 and thickness of 20 mil. On the other hand, this thesis also emphasizes on overcoming the problem of measuring the circuit with input and fixture that cause the reflection and phase shift.
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Chen, Ying-Yu, and 陳瀅羽. "A Study of Characteristic Impedance Analysis of Substrate." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/95738655369772320352.
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碩士<br>國立高雄第一科技大學<br>電腦與通訊工程研究所<br>100<br>Impedance matching would impact the quality of the signal transfer in the substrate design with high-speed signal transmission. Good impedance matching can design high-frequency signal transfer completely to the load point. Not reflect the signal back to the point of origin and cause noise, and thus enhance energy efficiency.
Design a transmission line structure, In addition to understanding all of the elements(Line width / Path...etc), we also have to understand the suppliers’ capabilities of substrate process. Differential signaling to suppress common mode noise is better than the single-ended signal transmission. So by simulating a substrate characteristic impedance from the Ansoft tool, and actually measuring differential signaling DOE (Design of Experiment) for 175/180 um substrate to verify the design rule of Z_diff=105+/-15 ohm.
To analysis dielectric and ground layer of characteristic impedance effect form the DOE, we can design the best impedance of substrate by controlling the transmission line, path and material.
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Hickerson, Anna Iwaniec. "An Experimental Analysis of the Characteristic Behaviors of an Impedance Pump." Thesis, 2005. https://thesis.library.caltech.edu/1969/9/All.pdf.
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<p>When a fluid-filled pliant tube is connected to tubing of a different impedance, a net flow in either direction can be induced by periodically compressing the pliant section asymmetrically from the ends. An experimental analysis of the characteristic behaviors of such a pump has been done demonstrating interesting results not predicted by prior analytical and computational results. Measurements show a complex non-linear behavior in response to the compression frequency, including distinct resonance peaks and reversals in flow direction. Ultrasound imaging provided a unique view of the tube wall and flow within, allowing us to visualize the wave propagation and reflection. Measurements include transient responses, resonant responses, and bulk flow behaviors for a variety of configurations. Net flow rates can exceed the volumetric displacement done by active compression demonstrating that, as a first approximation, this pump can have a higher efficiency than peristaltic pumping. Elasticity has been shown not to be a necessary factor in stimulating net forward flow.</p>
<p>Results from this study have helped show that a zebrafish (a model for human cardiac development) may utilize impedance pumping to drive circulation in early embryonic stages prior to valve formation as opposed to peristaltic pumping as was once thought. Additional research is being conducted to develop a micro-scaled version with applications in medicine, heat transfer, lab-on-chip technology, and micro-mixing.</p>
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Lai, Min-Feng, and 賴民峰. "Characteristic Evaluation and Biodetecting Application of Self-Assembled Monolayer by Electrochemical Impedance Spectroscopy." Thesis, 2004. http://ndltd.ncl.edu.tw/handle/86752298780937809690.
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碩士<br>國立成功大學<br>醫學工程研究所碩博士班<br>92<br>By using self assembled monolayer (SAM) with different functional groups to modify a substrate, the surface of the substrate was suitable for specific bio-detection. The aim of this study were two, one was to characterize the physical properties of substrate with SAM modification, the other was that applied a layer of SAM coated with avidin protein on sensing electrode as a bio-probe to quantify the formation of avidin-biotin complex by impedance response in electrical impedance analysis.
There were three types of SAM with carboxyl group to be coated on sensing electrodes by organic solvent which were DTBA, MUA and MHA. For making biotin probe, we use EDC/NHS reagent to activate the SAMs’ COOH to bind the avidins’ NH2 group. Circuit model is established by comparing with impedace response of DTBA, MUA and MHA after modification on the electrodes. In the circuit model, Ret and Cdl element represent density and chain length of SAM respectively. Rs element represents the resistance of supporting solution. Using circuit model to characterize SAM, we have several conclusions. (1) When modified time of SAM is about 60 minutes, SAM arives to saturate. (2) The longest SAM is increase in resistance and decrease in capacitance. (3) The saturated concentration of MUA solution is 10 mM. (4) Using dropping method, SAM becomes denser and modified time for SAM is reduced to 20 minutes as compared to immersion method. (5) Hydrophobic SAM is denser than hydrophilic SAM. For bio-detection, the linear range of biotin is 2-10 μg/ml bu means of △Ret and △Cdl. Correlation factor of Ret element (0.9943) is higher than that of Cdl (0.9624). Sensitivity of Ret and Cdl are 30.27 kΩ/μg/ml and 3.49×10-5 nF-1/μg/ml, respectively. Base on the findings above, we choose Ret element to the quantify concentration of biotin.
In summary, EIS not only is used to characterize SAM modified electrode, but also provids good linear range and reproducibility to detection of avidin-biotin complex. To develop biosensing technique, simulation circuit and impedance analysis could be applied to detection of biotin derivative（such as biotin labled antibody or DNA）and affinity biosample.
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Lin, Chia-Ching, and 林佳慶. "Electrical Characteristic Measurements and Discrimination of Bioparticles by Electrorotation and Impedance Measurement Method." Thesis, 2004. http://ndltd.ncl.edu.tw/handle/13387944642998766509.
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碩士<br>國立臺北科技大學<br>製造科技研究所<br>92<br>In this thesis, a novel microelectrode chip for Bio-particle’s permittivity and conductivity measurement is manufactured by MEMS technique. Using this chip, we can measure the electrical characteristic of cells and bacteria through employing DEP effect with un-contact method.
Experiments are implemented by using ROT method to measure permittivity and conductivity of a series of cells and bacteria progressively. In the beginning, it is to realize the principle of EP and DEP, design the shape of electrode and simulate the electric field distribution. Then, several main steps of the experiments are implemented:（1）Different conductivity of medium: Use KCL to obtain different conductivity medium, then drive and measure bio-particle to get different result. In this way, we can obtain different critical point with different medium conductivity and range of positive and negative DEP effect. (2) The property change of Bio-particle: Change the operation factor by heating or infecting particles by virus, then compare with normal ones. (3) Declination of bio-particle: Measure the activity change of bio-particle and its tendency response on the characteristic curve of ROT.
In the result of experiment, we measure the small difference of particle by physical method successfully instead of the traditional chemical method, so that it can save time to wait making a chemical assay. In addition, using DEP force can move and collect bio-particles. Base on the small difference of characteristic among bio-particles, it can use electric field effect to separate and purify them. Furthermore it can provide important data for integrated Bio-chip. In the feature, because of employing MEMS technology to fabricate micro-electrode and micro-channel, a pure “physical” biochip may be achieved through manipulating the bio-particle by DEP or EP force and measuring their electrical properties. Since Biochip is low cost and high efficiency, it may be more advantageous than chemical assay.
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LI, YI, and 李奕. "Contactless Sensing Levels of Tilt Liquid with the Impedance Characteristic of Interdigital Vertical Electrodes." Thesis, 2019. http://ndltd.ncl.edu.tw/handle/qezsa6.
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碩士<br>聖約翰科技大學<br>電機工程系碩士班<br>107<br>At present, most of liquid level measurements usually adopt the way in which the sensing electrode directly invades the liquid. It will cause corrosion, dissolved pollution and chemical reaction to affect the exact value. This is not suitable for medical, chemical liquids and foods, and there is no guarantee of pollution-free sensing.
Therefore, this paper proposes the use of equivalent capacitance impedance characteristic to implement the liquid level measurement by the outside of the container. The design methods including: 1). using a pulse wave signal to analyze the impedance change of capacitor. 2). using the dielectric of the capacitor principle to establish optimal electrode transfer signal and solution impedance matching of the spatial wave impedance sensing design. 3). using staggered vertical interdigital electrode to overcome the tilt error and improve the accuracy of sensing. The feature is when the liquid level in the container rises, it will increase in proportion to the equivalent capacitance of the liquid.
In this paper, the liquid level is obtained by the voltage amplitude variation of the non-contact liquid sensing device. The results revealed a linear relationship between liquid height and voltage amplitude. It shows that when the liquid level rises, the sensing area increases, and the equivalent capacitance increases to lead the amplitude signal increases. The approximate voltage signals are also obtained when the container or liquid is tilted. The establishment of the sensor is modified and verified by mathematical theory, and the copper foil of the printed circuit board is directly used as the sensing electrode, which has the effects of low power consumption and low cost. The real-time variation of the liquid level in the container is known from the voltage amplitude. The proposed work can be used in drinking water, medical or hazardous solutions to improve safety, also can be used in corrosive and acidic environments.
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Jhih-LinHong and 洪誌臨. "Electrical Characteristic Analysis of Various Cancer cells Using Microfluidic Device Based on Single-cell Impedance Measurement." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/13971992343465213263.
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碩士<br>國立成功大學<br>奈米科技暨微系統工程研究所<br>98<br>Electrical impedance spectroscopy (EIS) technique is used to analyze the character of electrochemical material for biomedical application. This paper presents a fast and low-cost manner to differentiate the four kinds of cells using impedance measurement in different voltage and frequency. Four kinds of cells (HeLa, MDA-MB-231, A549 and MCF-7) are analyzed and characterized on impedance by a trap-and-measure device. The impedance spectrums are obtained by the impedance analyzer at operating voltage of 0.2-1V and frequency from 20 to 101 kHz. According to the magnitude of impedance measurement, 0.4 V is the optimized operating voltage to distinguish the four kinds of cells most significantly. For the same cell line (MDA-MB-231 and MCF-7), the magnitude and phase are both distinguishable at 1.0V. In addition, an equivalent circuit model is established and fits with the experimental results. The circuit can be modeled electrically as cell impedance in parallel with capacitance of interfacial geometric per unit length of the electrode layout and in series with a pair of cell spreading resistance. The maximum decrease of the cytoplasm resistance occurs at different segments of operating voltage. For the A549 cell, the MDA-MB-231 cell, the MCF-7 cell and the HeLa cell, the maximum resistance variations are in 0.8-1.0V，0.8-1.0V，0.6-0.8V, and 0.4-0.6V, respectively. Because a strong electric filed may increase the exchange of ions between the cytoplasm and the culture medium.
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Schulz, Frederick Fay. "Development of a new method of measuring the characteristic impedance and complex wave number of a porous acoustic material." Thesis, 1987. http://hdl.handle.net/10945/22241.
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Yu, Ming-Yuan, and 游茗元. "Prediction of the Characteristic Impedance for Flexible Printed Circuit Using Hybrid Approaches:A Case Study on X Company in Taiwan." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/szqp77.
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碩士<br>輔仁大學<br>統計資訊學系應用統計碩士在職專班<br>103<br>High frequency is the trend for electrical products. The appropriate control of characteristic impedance is the key step to the success of FPC process.The issue of shorten the lead time for setting characteristic impedance and speed up producing time are extremely important for FPC process. Typically,FPC companies face many difficulties when performing simulations of controlling characteristic impedance, because it is not suitable for the higher price or professional electrical program needed. How to efficiently predict and accurately evaluate the characteristic impedance, it is the issue and cannot be ignored. This paper used test data as a benchmark to predict the characteristic impedance. The purpose of this study is to predict the characteristic impedance by using important explanatory variables. The proposed approaches include Multiple Regression(MR),Artificial Neural Network(ANN),Multivariate Adaptive Regression Splines(MARS), MRANNand MARS-ANN. The experimental results show that the ANN approach has the best accurate performance among those six methods. In addition, the MR-ANN and MARS-ANN are suggested to be used for the purpose of convenience.
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Chen, Shyue-Dar, and 陳學達. "Characteristic Impedance and Propagation of the First Higher-Order Microstrip Mode in Frequency and Time Domain/ Design a Series-fed, Proximity Coupling, Leaky-mode Antenna Array." Thesis, 2001. http://ndltd.ncl.edu.tw/handle/42500119822665443572.
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博士<br>國立交通大學<br>電信工程系<br>89<br>This thesis consists of two parts, including 1) experimentally and theoretically confirms the validity of the definition proposed by N. K. Das [4] for computing the complex characteristic impedance of the first higher-order (EH1) microstrip mode.
2) theoretically and experimentally demonstrates to design a millimeter wave leaky-mode antenna array based on the first higher-order mode on the printed microstrip line.
In the first part of the thesis, the normalized complex propagation constant and complex characteristic impedance of the microstrip obtained by the rigorous full-wave integral equation method is also presented. To better understand the circuit behavior of the leaky mode at the respective frequencies, the results are analyzed in both frequency and transformed steepest descent plane. A differential TDR (Time Domain Reflectometry) experiment shows that the experimental results agree excellently with the time-domain plots obtained theoretically by the Inverse Discrete Fourier Transform of the transmission line modeled by the dispersive characteristic. The propagation characteristics of the echoed signals in time-domain, which are reflected from the open-end of the leaky line, are analyzed in detail using the corresponding group velocity of the EH1 mode. The wide spread of the echoed signals in the time-domain is the direct result of the highly dispersive group velocity. The slowest group velocity is in the leaky region. The time-to-frequency conversion of the measured TDR data reveals that the reflection, leaky and propagation zones coexist simultaneously for the EH1 mode propagation. The conversion also accurately assesses the attenuation constant of the EH1 mode if the attenuation is not too high. The Fourier transform of the TDR responses also simultaneously yields the input reflection coefficient (S11) and the complex characteristic impedance. The complex characteristic impedance extracted from the TDR responses also agrees closely with the theoretical data.
In the second part of the thesis, proposed a series-fed, proximity coupling, N-element, leaky-mode microstrip antenna array, consisting of one 50ohm series-feeding line and N leaky lines. The design explored three analytic methods, included 1): the 2D full-wave analysis to get the propagation constant of the leaky-mode, 2) 3D space-domain integral equation for validating parameter of field pattern, determining the coupling coefficient and providing the vector current distribution, 3) General matrix-pencil method for extracting the amplitude of leaky-mode excited by the feeding-line. The design goal of this demonstration approaches 5o pencil- beam that be reached by this presented and validated by experiment.
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Kaur, Sukhdeep. "An empirical study of SD signal delay versus temperature in a plenum grade coaxial cable." Thesis, 2010. http://hdl.handle.net/2152/ETD-UT-2010-12-2534.
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A high resolution speedy delivery time domain reflectometer (SD/TDR) has been developed in the Electrical Engineering department at The University of Texas at Austin. The SD/TDR uses a novel non-sinusoidal signal that does not undergo dispersion during transmission in a lossy media. SD/TDR is used to estimate the length and detect the location of faults in the transmission lines. Time of flight (TOF) is one of the critical parameters of SD/TDR and a function of several temperature dependent factors. Given the TOF and length of a transmission line, signal delay can be computed. This research presents an empirical study of the effect of temperature on the TOF in a plenum grade coaxial cable for temperatures ranging from -3 °C to 60 °C. We also study the effect of temperature on characteristic impedance of the coaxial cable. Finally, a SD double exponential waveform is used to estimate TOF for calibrated short and open terminations.<br>text
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WANG, JYUN-JIE, and 王俊傑. "Preparation conductive composites and impedance characteristics." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/52223991326489474626.
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碩士<br>東海大學<br>化學工程與材料工程學系<br>103<br>The purpose of this study is to develop a uniform conducting composite coating through electro-polymerization for corrosion prevention. The composite system consists of polythiophene embedded in epoxy matrix.The electro-polymerization systems contained monomer with acetonitrile was used as the solvent, and tetrabutylammonium tetrafluoroborate (TBATFB) was the electrolyte that catalyzed the reaction of epoxy. Effects of the reactant concentrations, electrolyte concentration, and polymerizing potential were investigated.
Our results showed that comparing with pure polythiophene, composite systems required higher voltage and much higher thiophene monomer concentrations. Both the surface morphology and electrochemical properties varied significantly with the polymerization conditions. The polarization impedances of the composites increased with epoxy concentration, but decreased with increasing thiophene and TBATFB.High level of epoxy and TBATFB flattened the coating surface. Thiophene on the other hand, generated island structures on the surface.
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Tuan, Nguyen Anh, and 阮英俊. "Study on Characteristics of a Valveless Impedance Pump." Thesis, 2005. http://ndltd.ncl.edu.tw/handle/57000127976615229284.
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碩士<br>大葉大學<br>車輛工程學系碩士班<br>94<br>In this work, we have conducted the experimental and theoretical
investigations of characteristics of a valveless impedance pump. The
valveless impedance pump was constructed of an electric-mechanical
compression mechanism, an elastic tube, a rigid tube and two reservoirs.
The elastic tube of latex rubber was connected to the rigid plastic tube
and formed asymmetry impedance. The two tubes were glued to two
acrylic reservoirs, respectively. Through cumulative effects of wave
propagation and reflection originating from a compression
electric-mechanical mechanism located at the different position along
the length of the elastic tube, a pressure across the pump can be built up
to drive the flow. The experimental results show the flow is reversible
and the pressure heads are highly dependent on the frequency, amplitude
wave form and location of compression. Maximum flow rate of 2.45
l min1 at 42 Hz has been achieved with an elastic tube 50mm in length
and 6mm in inner diameter. Measurements show a complex non-linear
behavior in response to the compression frequency.
In the theoretical work, we have modeled such a system as a flat
tube with unsteady and one-dimensional flow, Euler’s equation with
appropriate boundary conditions. Analytic solutions calculated were
compared with experimental flow rates. Similar responses of flow rates
to actuating frequencies were observed.
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Chen, John, and 陳正中. "Guidance Characteristics of Two-Dimensionally Periodic Impedance Surface." Thesis, 1999. http://ndltd.ncl.edu.tw/handle/35809117587181890962.
Full textAbstract:
碩士<br>國立交通大學<br>電信工程系<br>87<br>We present here an exact formulation for the three-dimensional boundary-value problem of wave guiding by a two-dimensionally periodic impedance surface in a uniform medium. The dispersion characteristics of such a structure are rigorously analyzed in terms of the complete set of both TE- and TM-polarized plane waves in the uniform medium. The results are systematically expressed in the form of the Brillouin diagram; thereby, in comparison to the one-dimensional case, a host of new and interesting phenomena are identified and physically explained.
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Ju, You-Liang, and 朱祐良. "Characteristics Analysis of NFinFET Transistor and RFIC Impedance Matching." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/36135833619090152671.
Full textAbstract:
碩士<br>明新科技大學<br>電子工程系碩士班<br>103<br>It shall be the must to shrink the sizes of electronics devices in the Integrated Circuit Industry, which uses silicon or semiconductor as substrate. As the sizes get shrunk, the manufacture cost will be tremendously lowered and thus be competitive. Nevertheless, the quantum effects become apparent such that the devices confront issues, such as large Ioff. This leakage current is too large to satisfy the requirement of controllability. Conventional MOSFET is mandatorily replaced by FinFET, which is 3-D structural. The fin of FinFET, treated as a channel, partly gets strongly inversed within 10nm or 20nm, and the rest is wholly depleted as Gate polysilicon is applied with a bias. There forms a barrier to protect the device from being leaky. This device standing on insulator (silicon on insulator, SOI) is thus fully controllable and promising. One uses a technique fitting the current-voltage characteristics curves to abstract meaningful parameters, where many electrical characteristics and performances will be explored through these associated values.
In addition, Radio Frequency Integrated Circuit includes many components as a system, where the components are closely working together to accomplish the decoding and encoding functions. The signals are transmitted or received from one another. The impedance matching is mandatorily required among all the components. One specifically focuses on the impedance matching using advanced design system (ADS) by Agilent and tries to observe the correlation associated with inductor and capacitor in series or in parallel.
46
WANG, CHIEN-LI, and 王建力. "Characteristics Analysis of PFinFET Transistor and RFIC Impedance Matching." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/26617096145756088237.
Full textAbstract:
碩士<br>明新科技大學<br>電子工程系碩士班<br>103<br>Semiconductor uses the mechanism that the channel is strongly reversed to conduct Source and Drain. As the length of the channel is shorten, the rest part of the substrate, except the to-be-strongly-inversed part close to the gate oxide, becomes so leaky that the conventional device is no longer controllable. Instead, the 3-D channel of FinFET looking like a fin can be simultaneously strongly-inversed and used as a barrier that would protect the device from being leaky. The channel length can then be any shorter beyond 4nm. It is so promising that 28nm, 20nm, 16nm, 14nm, 10nm, and even 7nm are on the road. The barrier is formed because of being fully depleted in the fin. One thus focuses on the electrical performances of FinFET devices by fitting the characteristic curves coming from the measurement. Some meaning engineering quantities can then be abstracted and studied.
Moreover, radio-frequency integrated circuit using Agilent Design System (ADS) on Low Noise Amplifier (LNA) is posed to especially look at the impedance matching. RFIC with central frequencies, such as 5.8GHz, 6.0GHz, 6.4GHz, 6.5GHz, and 7.0GHz, are exactly tuned to reach the corresponding zero reflective coefficients, which appear at the center of Smith Chart. In the matching procedure, inductor and capacitor in parallel or in series are added to match the standard value which is 50Ohm. The relation between Gamma (reflective coefficients) and the impedance were examined carefully, and the moving Gamma is tracked, too.
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Li, Charles, and 李悌暘. "Scattering and Guiding Characteristics of Doubly Periodic Impedance Surface." Thesis, 2000. http://ndltd.ncl.edu.tw/handle/72314336628344558238.
Full textAbstract:
碩士<br>國立交通大學<br>電信工程系<br>88<br>We present here a study of wave phenomena associated with a doubly periodic impedance surface, e.g., an impedance surface that is modulated by two periodic functions of different periods in the same direction. Our main interest is in the interaction between the two different periods to explore new physical phenomena that cannot be taken place in the singly periodic case. Such a structure permits a rigorous formulation as a three-dimensional boundary value problem, so that any new physical phenomenon can be identified with confidence.
Here, the periodic impedance surface consists of two different periods in the x direction and no variations in the y direction. The studies of singly periodic structure can be found in the literature [1][2][5], and this paper can be viewed as an extension based on the knowledge of these studies. Due to the interactions between the two periods, we find some new guiding characteristics in this doubly periodic structure. With these additional characteristics, they can be utilized as several broad band elements. In the study, we investigate the general dispersion characteristics of such a structure using a useful method by presenting both TE- and TM-polarized plane waves in the uniform medium [1]. And gradually, we observe our experiments on the following cases, such as: the differences between commensurate and non-commensurate ones; two closely separated periods; modulation indices'' effects on the attenuation constants; etc. Thus, the scattering and guiding characteristics are generally presented.
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Huang, Amn-Jyh, and 黃安志. "Impedance characteristics and Heating perfomance of Insulated Antennas in Lossy Dielectric." Thesis, 1997. http://ndltd.ncl.edu.tw/handle/61509304687102242455.
Full textAbstract:
碩士<br>國立交通大學<br>電信研究所<br>85<br>Two different types of insulated antenna,namely,an insulated
coaxial slot antenna(ICSA) and an insulated dipole antenna(IDA)
are often emplyed in microwave hyperthermia. However,Zhang et
al. followed the impedance model which is only applicable to IDA
to analyze ICSA while ignoring the effect of the excess current
path inherent in an ICSA. In this sthdy, a suit of uniformly
insulated coaxial slot antennas(U-ICSAs) and uniformly insulated
dipole an-tenna(IDA),which have the same antenna length,were
investigated. In all cases,with a quarterwavelength choke
mounted,the impedance of the antennas remained constant
regardless of thevaring insertion depth into the phantom. From
the comparison of the U-IDA and U-ICSAs,theeffect of the excess
current path among ICSAs was identified. Moreover,based on the
obtained result, the effect of the excess current path was also
applied to shorten the length of oneU-ICSA without degrading its
impedance matching performance. The nonuniformly insulated coax-
ial slot antenna(NU-ICSA) has the improved tip heating
performance. However,the wave number inthe second arm is so
small that the resonance length becomes much longer than the
uniformlyinsulated antenna. With the antenna length increased,
the current and SAR distributions stretch toward the generator.
Experimentally measured results show that the U-ICSA,with its
length sho-tened by excess cureent path,exhibits more uniform
and concentrated axial SAR distribution thanthe NU-ICSA
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Wang, Lu Kai, and 王律凱. "The Influence of an Electrolyte on Impedance Characteristics in RuS2 Electrodes." Thesis, 1996. http://ndltd.ncl.edu.tw/handle/25393860893881177115.
Full text
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Yu-FanChang and 張宇帆. "Electrochemical impedance characteristics of dual-conduction composite cathode for IT-SOFC." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/e666e9.
Full textAbstract:
碩士<br>國立成功大學<br>材料科學及工程學系<br>103<br>Lanthanum-strontium manganite (LSM) was the classic cathode material for SOFCs due to its high stability in oxidizing atmospheres, and sufficient electrical conductivity at high temperature (~200S/cm at 800℃). However, insufficient ion conductivity of LSM restricted its oxygen reduction reaction (ORR) to the cathode/electrolyte interface where consist of electronic conductor, ionic conductor, and gas phase (Triple phase boundary, TPB). Several researchers have reported a method to significantly lower cathode polarization resistance (RP) by introducing ionic conductor into SOFCs cathode. Yttria-stabilized bismuth oxides (YSB) which exhibit high ionic conductivity and excellent oxygen electrocatalysis were mixed with nano-sized LSM to form composite cathodes. The extension of ORR site tends to enhance the reaction rate and decrease polarization resistance of the cathode.
In addition, the rate-determining steps for the ORR in bismuth oxide base composite cathode also needs to be explored. In this study, the electrochemical performances of composite cathodes with different LSM:YSB ratio were investigated using electrochemical impedance spectroscopy at various temperatures ranging from 500℃ to 650℃. The YSB content in composite may affect the catalytic activity toward the ORR. However, excessive YSB fraction may cause discontinuity in electronic pathway and then limit ORR of cathode.
To investigate the influence of electrolyte to cathode performance. Yttria-stabilized zirconia (YSZ), samarium-doped ceria (SDC), and YSB electrolyte were used to compare the composite cathode performance with different ionic conductivity electrolyte (ionic conductivity YSB〉SDC〉YSZ). The electrolyte with low ionic conductivity will increase the impedance of oxygen ion incorporation into oxygen sublattice. The interface of cathode /low ionic conductivity electrolyte limit the cathode performance by increasing polarization resistance.
The RP of LSM-YSB composite cathode shows lowest RP of 0.09 ohmcm2 at 650℃ when the volume fraction of YSB is 70%. The low RP measured from composite cathode is due to the high catalytic ability and sufficient electronic conduction. With the measurement and analysis of polarization impedance, better understanding of the cathodic reaction is achieved.