Дисертації з теми "The current-voltage characteristic"
Щоб переглянути інші типи публікацій з цієї теми, перейдіть за посиланням: The current-voltage characteristic.
Оформте джерело за APA, MLA, Chicago, Harvard та іншими стилями
Ознайомтеся з топ-50 дисертацій для дослідження на тему "The current-voltage characteristic".
Біля кожної праці в переліку літератури доступна кнопка «Додати до бібліографії». Скористайтеся нею – і ми автоматично оформимо бібліографічне посилання на обрану працю в потрібному вам стилі цитування: APA, MLA, «Гарвард», «Чикаго», «Ванкувер» тощо.
Також ви можете завантажити повний текст наукової публікації у форматі «.pdf» та прочитати онлайн анотацію до роботи, якщо відповідні параметри наявні в метаданих.
Переглядайте дисертації для різних дисциплін та оформлюйте правильно вашу бібліографію.
1
Lochner, Georg Philip. "The voltage-current characteristic of the human skin." Pretoria : [s.n.], 2005. http://upetd.up.ac.za/thesis/available/etd-09212005-093111/.
Повний текст джерела
2
Hurtig, Tomas. "Dynamics of the Current-Voltage Characteristic and the Potential in a Triple Plasma Machine." Thesis, KTH, Alfvénlaboratoriet, 1997. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-39337.
Повний текст джерелаАнотація:
A model for the static current voltage characteristic of a thin collisionless plasma inwich an electrical double layer is present is used for simulating the behaviour of anelectrical circuit in wich the plasma is a component. The numerical results thusobtained are compared to experimental results and found to be quite accurate forlow frequencies and amplitudes. The discrepancy between simulations andexperiments are found to be caused mainly by effects of hysteresis in the plasma.The hysteresis is then shown to be caused by 'slow ions'. The hysteresis is dividedinto three typical cases and a method to predict wich case to expect for a certaincombination of applied potential and frequeny is presented. The formation of thedouble layer in time and space is also studied by means of Langmuir probe measurements. Comments are also made concerning the internal plasma potential for different frequencies of the applied potential.
3
Гринько, Д. О., Д. О. Гринько, D. O. Grynko, О. П. Дмитриев, О. П. Дмитриев, O. P. Dimitriev, П. С. Смертенко, et al. "Injection Spectroscopy of Deep Traps in Nanostructured Films of Cadmium Sulfide." Thesis, Sumy State University Publishing, 2013. http://essuir.sumdu.edu.ua/handle/123456789/33901.
Повний текст джерелаАнотація:
Nanocrystallin CdS films with controlled stoichiometry deposited by CSVS were investigated by meth-
od of the current-voltage characteristics in ITO/CdS /In structures. It was shown that in the case of cadmi-
um excess (S
4
Grynko, D. O., O. P. Dimitriev, P. S. Smertenko, O. M. Fedoryak, Анатолій Сергійович Опанасюк, Анатолий Сергеевич Опанасюк, Anatolii Serhiiovych Opanasiuk, et al. "Injection Spectroscopy of Deep Traps in Nanostructured Films of Cadmium Sulfide." Thesis, Sumy State University, 2013. http://essuir.sumdu.edu.ua/handle/123456789/35240.
Повний текст джерелаАнотація:
Nanocrystallin CdS films with controlled stoichiometry deposited by CSVS were investigated by meth-od of the current-voltage characteristics in ITO/CdS /In structures. It was shown that in the case of cadmi-um excess (S
5
Svrček, Milan. "Metody pro dosažení maximálního výkonu FV modulů." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2017. http://www.nusl.cz/ntk/nusl-318171.
Повний текст джерелаАнотація:
This diploma thesis deals with the tracking of the maximum power point for photovoltaic panels and the methods used to achieve it. On this basis, two methods were designed and programmed and subsequently tested on three types of photovoltaic panels. In conclusion methods were appraised.
6
Alkan, Cemil. "Synthesis, Characterization And Electrical Properties Of Diazophenylene And Diazodiphenylene Bridged Co, Ni, Cu, Ce, And Er Phthalocyanine Polymers." Phd thesis, METU, 2004. http://etd.lib.metu.edu.tr/upload/2/12605362/index.pdf.
Повний текст джерелаАнотація:
SYNTHESIS, CHARACTERIZATION, AND ELECTRICAL PROPERTIES OF DIAZOPHENYLENE AND DIAZODIPHENYLENE BRIDGED Co, Ni, Cu, Ce, AND Er PHTHALOCYANINE POLYMERS
Alkan, Cemil
M. Sc., Department of Polymer Science and Technology
Supervisor: Prof.Dr. Leyla Aras
Co- Supervisor: Prof.Dr. Güngö
r Gü
ndü
z September 2004, 112 pages In this research, diazophenylene and diazodiphenylene bridged metal-phthalocyanine polymers were produced from diazonium salt of diaminophenylene/bensidin and pre-synthesized tetraamino metal phthalocyanines. Tetraamino metal phthalocyanine complexes of Co, Ni, Cu, Ce, and Er were obtained by reducing tetranitro metal phthalocyanine complexes synthesized from 3-nitrophthalic anhydride, urea, metal salt, and ammonium molybdate catalyst. Complexes and polymers were characterized by Fourier Transform Infrared Radiation (FTIR) and UV-Visible spectroscopies. X-Ray analysis showed that there were short range orientations in the polymers. Thermal analysis of the complexes and the polymers were done by differential scanning calorimetry and thermal gravimetric analysis at a heating rate of 10&
#61616
Cmin&
#61485
1 under nitrogen atmosphere. Ash analysis was performed to determine the metal content of the polymers. Viscosity and ebullioscopy measurements of the soluble part of the polymers were carried out in THF at 25&
#61616
C. Scanning electron microscopy were used for morphology investigations of the polymers. Four probe conductivity measurements showed that electrical conductivity of the polymers increased according to the metallic conductivity of the metal at the center of the phthalocyanine units. When doped with iodine, the polymer samples showed 104 fold increase in their conductivities. Current-Voltage (I-V) measurements showed that the polymers were optically sensitive and semiconductors. Electrochemical analysis of the soluble part of the polymers were determined in tributylamine perchlorite+dichloromethane mixture utilizing cyclic voltammetry (CV).
7
Шевченко, Сергій Юрійович. "Вплив вищих гармонік напруги на вибір та експлуатацію обмежувачів перенапруг для захисту систем електропостачання". Thesis, НТУ "ХПІ", 2015. http://repository.kpi.kharkov.ua/handle/KhPI-Press/18478.
Повний текст джерелаАнотація:
Дисертація на здобуття наукового ступеня доктора технічних наук за спецiальністю 05.09.03 - електротехнiчнi комплекси та системи. - Національний технічний університет "Харківський політехнічний інститут". Харків 2015 р.
Дисертація присвячена актуальній науково-технічній проблемі визначення пливу вищих гармонік напруги на вибір та експлуатацію обмежувачів перенапруг для захисту електротехнічних комплексів та систем, що має важливе значення та забезпечує підвищення ефективності та надійності функціонування систем електропостачання. В рамках даного напряму отримані наступні результати. Виконано аналіз існуючих вимог до вибору та експлуатації перенапруг нелінійних (ОПН) в системах електропостачання різних класів напруги; Проведено експериментальні дослідження електрофізичних характеристик варисторів та ОПН в зібраному стані провідних світових виробників при різних частотах прикладеної напруги та вольт амперних характеристик варисторів і ОПН в зібраному стані в зоні струмів витоку. Удосконалено математичну модель для вибору енергетичних характеристик ОПН при низькій якості електричної енергії в системі електропостачання на базі схем заміщення ОПН в зоні струмів витоку їх вольт-амперної характеристики (ВАХ). Запропановано метод визначення втрат активної потужності в ОПН на базі отриманих ВАХ в зоні струмів витоку, та проведено аналіз впливу несинусоїдальності напруги на величину енергії, що діє на ОПН, а також визначено вплив на нормальну роботу ОПН перенапруг грозового і комутаційного імпульсів струму та підвищеної напруги промислової частоти. Розроблено методи визначення ВАХ ОПН в зоні струмі витоку на основі отриманих експериментальних ВАХ ОПН, які базуються на нейронних мережах та апроксимацією ВАХ двома кривими першого порядку. Удосконалено математичну модель теплових режимів ОПН при низькій якості електричної енергії в системі електропостачання та виконані дослідження впливу різних чинників на теплову стабільність ОПН. Експериментально досліджено наявність порушень якості електричної енергії в системах електропостачання різних видів промисловості України. Удосконалено методи вибору ОПН в системах електропостачання різних номінальних напруг з низькою якістю електричної енергії. Сформульовані основні засади застосування та експлуатації ОПН при впливі вищіх гармонік напруги. Обгрунтовано використання тепловізорів та пірометрів для експлуатаційного контролю стану ОПН.The thesis for the degree of doctor of technical sciences, specialty 05.09.03 - Electrotechnical complexes and systems. - National Technical University "Kharkiv Polytechnic Institute". Kharkov 2015. Dissertation is devoted to actual scientific and technical problem of determining the effect of the higher harmonics of the voltage on the selection and exploitation of surge arresters for protection electricity supply systems is important and enhances the efficiency and reliability of power supply systems. In this area, the following results. The analysis of existing requirements for the selection and exploitation of surge arresters in electricity supply systems of different voltage classes. Experimental studies of electrophysical characteristics of varistors and surge arresters assembled the world's leading manufacturers in the different frequencies of the applied voltage and current voltage characteristics of varistors and surge arresters in an assembled state in the area of leakage current. Іmproved the mathematical model for selecting the energy characteristics of the arrester at a low power quality in the power supply system on the basis of equivalent circuits in the area of the arrester leakage current of the current-voltage characteristics (CVC). Offered the method for determination of active power losses in the arrester on the basis of the obtained current-voltage characteristics in the area of leakage current and the analysis of the impact of non-sinusoidal voltage to the amount of energy exerted on surge arresters, as well as determined the effect of the normal operation of surge arresters Surge lightning and switching current pulses and high frequency voltage. Developed the methods for determining the current-voltage characteristics in the area of the arrester leakage current on the basis of the experimental CVC arresters based on neural networks and approximation CVC two curves of the first order. Іmproved the mathematical model of thermal modes of surge arresters in low power quality in the power supply system and to study the effect of different factors on the thermal stability of the arrester. Experimentally investigated for poor quality of electricity supply systems of various types of industry of Ukraine; An improved method for selecting surge arresters in power supply systems of different rated voltages with low quality electric energy. Іmproved the basic principles for the use and operation of surge arresters under the influence of higher harmonic voltage. Justify the use of thermal imagers and pyrometers for operational monitoring of the arrester.
8
Шевченко, Сергій Юрійович. "Вплив вищих гармонік напруги на вибір та експлуатацію обмежувачів перенапруг для захисту систем електропостачання". Thesis, НТУ "ХПІ", 2015. http://repository.kpi.kharkov.ua/handle/KhPI-Press/18479.
Повний текст джерелаАнотація:
Дисертація на здобуття наукового ступеня доктора технічних наук за спецiальністю 05.09.03 - електротехнiчнi комплекси та системи. - Національний технічний університет "Харківський політехнічний інститут". Харків 2015 р. Дисертація присвячена актуальній науково-технічній проблемі визначення пливу вищих гармонік напруги на вибір та експлуатацію обмежувачів перенапруг для захисту електротехнічних комплексів та систем, що має важливе значення та забезпечує підвищення ефективності та надійності функціонування систем електропостачання. В рамках даного напряму отримані наступні результати. Виконано аналіз існуючих вимог до вибору та експлуатації перенапруг нелінійних (ОПН) в системах електропостачання різних класів напруги; Проведено експериментальні дослідження електрофізичних характеристик варисторів та ОПН в зібраному стані провідних світових виробників при різних частотах прикладеної напруги та вольт амперних характеристик варисторів і ОПН в зібраному стані в зоні струмів витоку. Удосконалено математичну модель для вибору енергетичних характеристик ОПН при низькій якості електричної енергії в системі електропостачання на базі схем заміщення ОПН в зоні струмів витоку їх вольт-амперної характеристики (ВАХ). Запропановано метод визначення втрат активної потужності в ОПН на базі отриманих ВАХ в зоні струмів витоку, та проведено аналіз впливу несинусоїдальності напруги на величину енергії, що діє на ОПН, а також визначено вплив на нормальну роботу ОПН перенапруг грозового і комутаційного імпульсів струму та підвищеної напруги промислової частоти. Розроблено методи визначення ВАХ ОПН в зоні струмі витоку на основі отриманих експериментальних ВАХ ОПН, які базуються на нейронних мережах та апроксимацією ВАХ двома кривими першого порядку. Удосконалено математичну модель теплових режимів ОПН при низькій якості електричної енергії в системі електропостачання та виконані дослідження впливу різних чинників на теплову стабільність ОПН. Експериментально досліджено наявність порушень якості електричної енергії в системах електропостачання різних видів промисловості України. Удосконалено методи вибору ОПН в системах електропостачання різних номінальних напруг з низькою якістю електричної енергії. Сформульовані основні засади застосування та експлуатації ОПН при впливі вищіх гармонік напруги. Обгрунтовано використання тепловізорів та пірометрів для експлуатаційного контролю стану ОПН.The thesis for the degree of doctor of technical sciences, specialty 05.09.03 - Electrotechnical complexes and systems. - National Technical University "Kharkiv Polytechnic Institute". Kharkov 2015. Dissertation is devoted to actual scientific and technical problem of determining the effect of the higher harmonics of the voltage on the selection and exploitation of surge arresters for protection electricity supply systems is important and enhances the efficiency and reliability of power supply systems. In this area, the following results. The analysis of existing requirements for the selection and exploitation of surge arresters in electricity supply systems of different voltage classes. Experimental studies of electrophysical characteristics of varistors and surge arresters assembled the world's leading manufacturers in the different frequencies of the applied voltage and current voltage characteristics of varistors and surge arresters in an assembled state in the area of leakage current. Іmproved the mathematical model for selecting the energy characteristics of the arrester at a low power quality in the power supply system on the basis of equivalent circuits in the area of the arrester leakage current of the current-voltage characteristics (CVC). Offered the method for determination of active power losses in the arrester on the basis of the obtained current-voltage characteristics in the area of leakage current and the analysis of the impact of non-sinusoidal voltage to the amount of energy exerted on surge arresters, as well as determined the effect of the normal operation of surge arresters Surge lightning and switching current pulses and high frequency voltage. Developed the methods for determining the current-voltage characteristics in the area of the arrester leakage current on the basis of the experimental CVC arresters based on neural networks and approximation CVC two curves of the first order. Іmproved the mathematical model of thermal modes of surge arresters in low power quality in the power supply system and to study the effect of different factors on the thermal stability of the arrester. Experimentally investigated for poor quality of electricity supply systems of various types of industry of Ukraine; An improved method for selecting surge arresters in power supply systems of different rated voltages with low quality electric energy. Іmproved the basic principles for the use and operation of surge arresters under the influence of higher harmonic voltage. Justify the use of thermal imagers and pyrometers for operational monitoring of the arrester.
9
Achenbach, Sven. "Beiträge zur analytischen Berechnung und Reduktion der aus Netzspannungsunsymmetrien resultierenden Harmonischen in Systemen der Hochspannungs-Gleichstrom-Übertragung." Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2010. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-38968.
Повний текст джерелаАнотація:
An AC system’s voltage unbalance by a fundamental frequency negative sequence system is usually the main cause for the emission of non-characteristic harmonics by current source converters as used in conventional HVDC systems. This emission takes place on both sides of each 12-pulse converter.
On the DC side mainly a 2nd harmonic voltage appears driving a 2nd harmonic current. The magnitude of this harmonic current can exceed the magnitudes of the characteristic harmonics even if no low order resonance exists. Further non-characteristic harmonics generated by the converter under such unbalanced supply voltage conditions have frequencies with a frequency distance to the characteristic harmonics of 2 times the fundamental frequency. The main technical drawbacks are the unintended coupling between both AC systems and the risk of thyristor over-stresses by DC current discontinuities at low power transfer levels.
On both AC sides the largest 2 non-characteristic current harmonics generated by a 12-pulse HVDC converter under unbalanced supply voltage conditions are a negative sequence system of the fundamental harmonic and a positive sequence system of the 3rd harmonic. Also on the AC sides further harmonics are emitted by the converter with a order number distance of 2 to the orders of the characteristic harmonics. However, in practical AC system operation special attention has to be paid to the 3rd harmonic distortion level, in particular when low order resonance appears between the system impedance and the impedance of the converter station AC filters.
In order to avoid the above mentioned problems, large smoothing reactors and sometimes large blocking filters are installed on the DC side and the voltage distortion on the AC sides is reduced by AC filters. However, these filters require an expensive high component rating if they are tuned to the 2nd or 3rd harmonic respectively.
The work shows that a modification of the valve firing can reduce the levels of the 2nd and 3rd harmonic without investment into additional primary equipment. Furthermore, this offers the chance to reduce the minimum power transfer level since also the risk of an intermittent DC current can be reduced. A corresponding algorithm and a control strategy are proposed.
However, the calculation of an appropriate firing pattern requires a detailed modelling of the processes within the converters, especially the formation of the harmonics and the harmonic transfer between AC and DC sides. The work proposes a component vector model for the calculation of the harmonics.
This model assumes that each harmonic consists of a first component representing the ideal conversion process, a 2nd component representing the impact of different commutation angles and in the case of the modified firing a 3rd component considering the impact of the intended non-equidistant firing.
The work shows, that the harmonic component vectors resulting from voltage unbalance and from firing modulation can be treated separately and superimposed linearly.
The calculation of the harmonic component vectors is performed applying the method of switching functions. For the consideration of the commutation and firing angle differences the modelling of switching functions based on differential impulses is proposed. However, especially an accurate representation of the above mentioned 2nd component vector requires a correct calculation of the commutation angles and their valve-specific differences.
The investigations of this work have revealed that the conventional method of calculating the commutation angles – assuming an ideal smoothed DC current - may not produce results of sufficient accuracy. This is especially true in the case of a high ripple of the DC current, e.g. smoothed with a small smoothing reactor. A small smoothing reactor is typical for HVDC back-to-back applications.
Therefore a new analytical method for the calculation of the commutation angles has been developed which in particular considers the typical pulse form of the DC current and additionally the impacts of the voltage unbalance and of the proposed modification of the firing on the ripple shape of the DC current.
Moreover, as this analytical method requires the instantaneous values of the DC current at the instants of valve firing, a further analytical method for the calculation of these discrete current values has been developed. The equations are valid under the same conditions as the new ones for calculation of the commutation angles, i.e. resistive-inductive AC system fundamental frequency impedances, any degree of DC current smoothing between ideal smoothing and a ripple at the limit for current discontinuities. Symmetrical conditions, supply voltage unbalances and non-equidistant firing as proposed are applied. It is shown that, using this method, also the discrete values of the DC current at the end of the commutation intervals can be determined. In practice one of these discrete current values indicates the minimum value during one period of the fundamental frequency. This offers the chance for a more exact analytical determination of the limit for the appearance of DC current discontinuities.
For typical parameters of a back-to-back installation the new methods and the new analytical equations have been compared with simulation results showing excellent correlation for typical voltage unbalances of not more than 1...2% and firing angle differences of not more than 2.5°. This verification is performed for the harmonics, the commutation angles and the discrete values of the DC current at the firing instants as well.
10
Špinar, Marek. "Ověření provozní výkonnosti a optimalizace FVE." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2016. http://www.nusl.cz/ntk/nusl-241950.
Повний текст джерелаАнотація:
The Master´s thesis deals with issues of operational performance of two photovoltaic power plants. In the thesis is stated the history of photovoltaics, description of photovoltaic effect, used materials and production technology of the most used material in PV industry – Silicon. The basic parts and parameters of photovoltaic power plant are described. Thesis also solves, how could be done the first and periodically control due to relevant directives. The ways of diagnostics potentional failures, methods of measuring and the exam of monitoring system are stated. Practice part is focused on measuring and comparing operational performance of FVE Kurdějov and FVE Šakvice II. Operational performance was calculated from exported data for years 2014 and 2015. The thesis also contains measuring of each string connected to inventors, which are installed on the power plant. The result is an identification of strings with decreased operational performance. Based on that was created recommendations for optimalization and increase of the performance. The last part is software for simulation of photovoltaic power plant. This SW calculates potentional energy, which could be produced in a day with available data export. The calculation is defined by parameters, which are assigned.
11
Божко, Костянтин Михайлович. "Вдосконалення методів та засобів контролю дефектів фотоелектричних сонячних батарей". Thesis, НТУУ "КПІ", 2016. https://ela.kpi.ua/handle/123456789/17647.
Повний текст джерелаАнотація:
Дисертацію присвячено вдосконаленню методів і засобів контролю дефектів фотоелектричних сонячних батарей, які збуджуються при протіканні темнового струму, та зменшенню похибки вимірювання вольт-амперних характеристик сонячних батарей.
Запропоновано метод динамічного вимірювання вольт-амперної характеристики фотоелектричних сонячних батарей на основі лінійної розгортки струму, який відрізняється від аналогів розширеним на 50 % діапазоном струму, підвищеною у 10 раз швидкодією, зменшенням у 10 раз виділенням джоулева тепла та зменшенням відносної похибки на 10%. Створено математичну модель динамічного вимірювання вольт-амперної характеристики, яка дозволяє проектувати пристрої лінійної розгортки струму із заданими параметрами, а також вдосконалено математичну модель фільтрації сигналу, застосування якої дозволяє компенсувати високочастотні коливання у вимірювальному колі фотоелектричних сонячних батарей.
Запропоновано метод нагрівання фотоелектричних сонячних батарей зворотним темновим струмом для контролю дефектів на ранній стадії розвитку та вдосконалено метод інфрачервоної термографії для вимірювання коефіцієнту теплопровідності клейових з’єднань, який забезпечив зменшення відносної похибки до 5% при стаціонарному теплообміні. Вдосконалено математичну модель методу телевізійного контролю дефектів фотоелектричних сонячних батарей, застосування якої дозволяє проектувати засоби вимірювання яскравісних і геометричних характеристик електролюмінісцентних дефектів.
Розроблено та виготовлено лабораторні стенди для контролю фотоелектричних сонячних батарей: динамічного вимірювання вольт-амперних характеристик із розширеним діапазоном потужності від 1 до 300 Вт та відносною похибкою вимірювання напруги 1%; телевізійного контролю електролюмінісцентних дефектів, який дозволяє вимірювати геометричні параметри дефектів з похибкою 5%.
Отримані результати впроваджено у технологію вимірювання вольт-амперних характеристик фотоелектричних сонячних батарей при їх експлуатації.Dissertation is devoted to the improvement of the methods and means of controlling the defects of photovoltaic solar cells, which are excited by the flow of dark current, and reduce measurement error of current-voltage characteristics of the solar cells. A method for dynamic measurement of current-voltage characteristics of photovoltaic solar cells based on linear current scanning, which is different from the analog expanded by 50% of the current range, increased 10-fold speed, a decrease of 10 times the release of Joule heat and a decrease in the relative error of 10%. A mathematical model of dynamic measuring current-voltage characteristics, which allows you to design a linear scanning device current with the specified parameters, and improved mathematical model of signal filtering, use of which is to compensate for high-frequency oscillations in the measuring circuit of photovoltaic solar panels. The method of heating the photovoltaic solar cells reverse dark current for controlling defects at an early stage of development and improved method of infrared thermography to measure the thermal conductivity of the adhesive joints, which provided a reduction of error of up to 5% at steady-state heat transfer. Improved mathematical model method TV control defects of photovoltaic solar panels, the use of which allows the design of measuring brightness and geometrical characteristics of electroluminescent defects. Designed and manufactured laboratory benches for control of photovoltaic solar cells : Dynamic measuring current-voltage characteristics with a power range from 1 to 300 W and the relative error of voltage measurement 1 % ; TV control electroluminescent defects , which can measure the geometric dimensions of the defects with an accuracy of 5 % . The results are incorporated in the measurement technology of the current- voltage characteristics of photovoltaic solar panels at their operation .
Диссертация посвящена совершенствованию методов и средств контроля дефектов фотоэлектрических солнечных батарей, которые возбуждаются при протекании темнового тока, и уменьшению погрешности измерения вольт-амперных характеристик солнечных батарей. Предложен метод динамического измерения вольт-амперной характеристики фотоэлектрических солнечных батарей на основе линейной развертки тока, который отличается от аналогов расширенным на 50% диапазоном тока, повышенным в 10 раз быстродействием, уменьшением в 10 раз выделения джоулева тепла и уменьшением погрешности на 10%. Создана математическая модель динамического измерения вольт-амперной характеристики, которая позволяет проектировать устройства линейной развертки тока с заданными параметрами, также усовершенствована математическая модель фильтрации сигнала, применение которой позволяет компенсировать высокочастотные колебания в измерительной цепи фотоэлектрических солнечных батарей. Предложен метод нагрева фотоэлектрических солнечных батарей обратным темновым током для контроля дефектов на ранней стадии развития и усовершенствован метод инфракрасной термографии для измерения коэффициента теплопроводности клеевых соединений, который обеспечил уменьшение погрешности до 5% при стационарном теплообмене. Усовершенствована математическая модель метода телевизионного контроля дефектов фотоэлектрических солнечных батарей, применение которой позволяет проектировать средства измерения яркостных и геометрических характеристик электролюминесцентных дефектов. Разработаны и изготовлены лабораторные стенды для контроля фотоэлектрических солнечных батарей: динамического измерения вольт-амперных характеристик с диапазоном мощности от 1 до 300 Вт и относительной погрешностью измерения напряжения 1%; телевизионного контроля электролюминесцентных дефектов, который позволяет измерять геометрические размеры дефектов с погрешностью 5%. Полученные результаты внедрены в технологию измерения вольт-амперных характеристик фотоэлектрических солнечных батарей при их эксплуатации.
12
Ren, Huilin. "Current Voltage Characteristics of a Semiconductor Metal Oxide Sensor." Fogler Library, University of Maine, 2001. http://www.library.umaine.edu/theses/pdf/RenH2001.pdf.
Повний текст джерела
13
Hrycík, Tomáš. "Porovnání použití přístrojových transformátorů a senzorů v aplikacích s ochranou REF 542plus." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2010. http://www.nusl.cz/ntk/nusl-218429.
Повний текст джерелаАнотація:
The aim of this Master´s thesis is use of instrument transformers and sensors on field of industry protection. We will compare current and voltage transformers, current sensor – based on Rogowski coil, voltage sensor – based on voltage divider. By this measure devices, we can monitoring values of analog quantities in medium voltage switchgear. It is impossible to compare, measure and analyze without this measure devices. There is protection terminal REF542plus, which can compile this values. The REF542plus ability are measuring, monitoring, remote control and protection. First, we will discuss about theory of sensors and convential instrument transformers and analysis of analog signal. We will compare analog input channel on sensor´s analog module and transformer´s analog module. There are few differences between type of analog modules. For analog signal analysis are important frequency filters and Analog/ Digital Convertor (sigma-delta). We will describe functions and options of REF542plus. In practical part of this project, we will test protection functions of protection terminal. First, protection terminal will be connected to sensors. Second protection terminal will be connected to transformers. For testing we chose Earth-fault directional protection and differential protection. We will make only secondary tests. That´s mean, input analog quantities to REF542plus will be simulated by tester. In all we will verify quality of protection. We will focus on lower settings of protection and we will inject protection by low current. Objectives are testing of trip characteristics and measuring of trip time.
14
Hrabal, Michal. "Nové diketopyrrolopyrroly pro organickou fotovoltaiku." Master's thesis, Vysoké učení technické v Brně. Fakulta chemická, 2013. http://www.nusl.cz/ntk/nusl-216971.
Повний текст джерелаАнотація:
The aim of this diploma thesis is to conduct optical and photovoltaic characterization of derivatives of diketopyrrolopyrrole (DPP) as materials suitable for fabrication of bulk heterojunction organic solar cells. The charge transfer from donor material (DPP) to acceptor material (PCBM) is studied by a quenching of fluorescence. The photovoltaic response is studied by current – voltage characteristic which can tell us crucial parameters such as shor circuit current density Jsc, open circuit voltage Voc, fill factor FF and power conversion efficiency PCE. Optical characterization was carried out for symmetrical DPP derivatives (U69 and U97) which both contained diphenylaminstilbene moiety and differed in N-alkyl group. On the other hand photovoltaic characterization was conducted for analogous but asymmetrical materials (U70 and U99). Material U29 was characterized as well but its properties proved to be very poor. Both these characterizations tell us that materials with shorter solubilization groups (U69 and U99) are more suitable candidates. Achieved PCE for U70 was 0,74 % and for U99 up to 1,39 %. From these values one can say that small molecule organic materials can be used for fabrication of solar cells.
15
Mutsuura, Keita, Hirotaka Shimizu, Yasunobu Yokomizu, and Toshiro Matsumura. "Flux flow resistance in Bi2223 generated by pulse currents." IEEE, 2005. http://hdl.handle.net/2237/6789.
Повний текст джерела
16
Babaev, A. A., P. P. Khokhlachev, Yu A. Nikolaev, E. I. Terukov, A. B. Freidin, R. A. Filippov, A. K. Filippov, and N. K. Manabaev. "Temperature Dependence of Resistivity and Current-Voltage Characteristics of the Films of Composites Based on Modified Carbon Multiwalled Nanotubes and Graphite." Thesis, Sumy State University, 2013. http://essuir.sumdu.edu.ua/handle/123456789/35160.
Повний текст джерелаАнотація:
A film composites based on modified multiwalled carbon tubes and polymer (95/5 wt. %) Respectively on paper, without the paper by directional spinning from the liquid phase and graphite. The temperature dependence of the resistivity () in the range T 77-410 K and the corresponding current-voltage charac-teristics. Detected irreversible transitions from semiconducting to metallic conductivity in carbon nono-trubkah and a maximum at T 340 K.
When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/35160
17
Franchi, Jimmy. "Investigation of the electronicstructures of single molecularjunctions from current voltage characteristics." Thesis, KTH, Skolan för informations- och kommunikationsteknik (ICT), 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-129288.
Повний текст джерелаАнотація:
Molecular electronics has lately shown significant progress due to rapid advances in investigative methods and is vital to the future of the electronic industry since the fundamental limits of the solid state transistors are closer than ever. To reach the application of using single molecules as electronic components, it is imperative to investigate the electronic structure of a single molecule connected to metal electrodes. This research has focused on examining current voltage behavior to clarify the electronic structure using transition voltage spectroscopy (TVS) and a single level tunneling (SLT) model. In an approximate model, TVS can be used to determine the molecule frontier orbital-electrode energy gap (EF -ξ0) and in most cases prove molecular presence in the junction. The SLT model can be tted to experimental data to obtain molecule-electrode bond strength and molecule-electrode energy gap. The measurement system prepared and tested was a mechanically controlled break junction. It has ability not only to test current voltage characteristics but also probe external magnetic and electric eld modulation eects. The current-voltage characteristics of benzenedithiol, hexanedithiol and a recently synthesized oligothiophene molecule with five thiophene rings were measured and analysed by using TVS and tting the SLT model. Most of the current-voltage characteristics could be tted using the SLT model. Analysis revealed that the variation in molecular conductance is mainly due to variation in molecule-electrode coupling strength and not due to the EF -ξ0 energy gap. Dierent EF -ξ0 were discovered for the three dierent molecules. It was shown that the transition voltage roughly approximates the EF -ξ0 energy gap by comparing the TVS results to the results obtained from fitting the SLT model.
18
Sosnowski, J. "Influence of Nano-defects on Current-voltage Characteristics of HTc Superconductors." Thesis, Sumy State University, 2013. http://essuir.sumdu.edu.ua/handle/123456789/35112.
Повний текст джерелаАнотація:
Theoretical analysis is presented of the influence on the current-voltage characteristics of the nanosized
defects, which may be created by heavy ions irradiation or can arise in technological process, for instance
during the winding procedure of the superconducting coil. Results of calculations, performed basing
on developed model of the interaction of pancake type vortices appearing in HTc superconductors with
nano-sized defects are presented. The energy balance for flux creep process is deduced and current-voltage
characteristics calculated in the function of static magnetic field, in accordance with experimental behavior.
This static analysis has been extended further on the case of the time-varying magnetic field in which
existence of dynamical anomalies is predicted, according to our previous experimental data.
When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/35112
19
Cipín, Radoslav. "Matematické modely transformátorů a asynchronních motorů." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2008. http://www.nusl.cz/ntk/nusl-217586.
Повний текст джерелаАнотація:
The fist part of this work is dealt with the construction of the mathematical models of voltage and current transformers. There are created and simulated models of voltage and current transformer with the nonlinear magnetization characteristics. The second part of this work is dealt with equivalent circuit of the induction motor in the form of Gamma-circuit. The speed-torque characteristic and the dependence of stator current on the slip are calculated from this equivalent circuit. The third part of this work is dealt with electromagnetic design of the alternating current machines by the help of a classic way and a new way.
20
Kondo, Takeshi. "Current-voltage characteristics of organic semiconductors interfacial control between organic layers and electrodes /." Diss., Available online, Georgia Institute of Technology, 2007, 2007. http://etd.gatech.edu/theses/available/etd-05022007-122219/.
Повний текст джерелаАнотація:
Thesis (Ph. D.)--Chemistry and Biochemistry, Georgia Institute of Technology, 2008.Dr. Marder Seth R, Committee Chair ; Dr. Kippelen Bernard, Committee Co-Chair ; Dr. Brďas Jean-Luc E, Committee Member ; Dr. Perry Joseph W, Committee Member ; Dr. Srinivasarao Mohan, Committee Member.
21
Skatkov, L. I., V. P. Gomozov, and S. G. Deribo. "Role of metal impurities in generation of defects in anodic layers of Nb₂O₅." Thesis, Institute of electrochemistry and energy systems "Academician Evgeni Budevski", 2015. http://repository.kpi.kharkov.ua/handle/KhPI-Press/45463.
Повний текст джерела
22
Nightingale, Wendy Denise. "Electrical characteristics if an identified insect motoneurone cell body : a current- and voltage-clamp." Thesis, University of St Andrews, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.329911.
Повний текст джерела
23
Shah, Syed Arif Ullah. "The impacts of series compensated EHV lines on distance protection, and a proposed new mitigation solution." Thesis, KTH, Elektroteknisk teori och konstruktion, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-209916.
Повний текст джерелаАнотація:
Series compensation is extensively applied to the transmission lines to increase the power transfer capability of transmission lines, reduce transmission losses, improve voltage profiles, and improve power oscillation damping and transient stability of power systems. But it modifies the apparent impedance of the transmission lines during fault conditions and might cause the distance protection of transmission lines to encounter directional discrimination issues and reach problems. The non-linear characteristic of metal oxide varistor in series compensation model creates further complexity to the fault analysis and might affects the performance of conventional distance protection scheme. The distance protection issues in the series compensated lines need to be addressed for the reliable and sustainable operation of power system.The directional discrimination issues related to current inversion and voltage inversion phenomenon, and reach problems related to sub-synchronous oscillation phenomenon are addressed in this thesis report. This report aims to analyse the impacts of series compensation on the performance of conventional distance relays, and proposes a new protection solution to mitigate the shortcomings of distance relays in the series compensated lines. The proposed new protection solution includes: new tripping characteristic of quadrilateral distance relays to cope with the steady-state reach problems due to current or voltage inversion, and a new high-pass filtering technique to handle the transient reach problems due to SSO.The proposed new protection algorithm is developed in MATLAB. The performance of new protection algorithm is evaluated by simulating a 500 kV two-source power system with a 200 km series compensated line in EMTDC/ PSCAD (Manitoba Hydro). The proposed new protection solution is found to be beneficial.Seriekompensation tillämpas i stor utsträckning på överföringsledningarna för att öka överföringsförmågan hos överföringsledningar, minska överföringsförluster, förbättra spänningsprofiler och förbättra effektdämpning och övergående stabilitet hos elsystem. Men det ändrar transmissionslinjernas uppenbara impedans under felförhållanden och kan orsaka att distansskydd för överföringsledningarna stöter på diskrimineringsproblem och uppnår problem. Den icke-linjära egenskapen hos metalloxidvaristor i seriekompensationsmodell skapar ytterligare komplexitet för felanalysen och kan påverka prestandan hos konventionella distansskyddssystem. Distansskydd problemen i seriekompenserade linjer måste lösas för en pålitlig och hållbar drift av elsystemet. De riktningsdiskrimineringsproblem som är relaterade till det aktuella inversions- och spänningsinversionsfenomenet och uppnår problem relaterade till subsynkron oscillationsfenomen tas upp i denna avhandlingsrapport. Denna rapport syftar till att analysera effekterna av seriekompensation för prestanda hos konventionella distansreläer och föreslår en ny skyddslösning för att mildra bristerna i distansreläerna i seriekompenserade linjer. Den föreslagna nya skyddslösningen innefattar: Ny utlösningskaraktäristik för fyrsidig distansreläer för att klara avståndet med stillastående / räckvidden på grund av ström- eller spänningsinversion och en ny högpassfiltreringsteknik för hantering av övergående över- Nå problem på grund av SSO. Den föreslagna nya skyddsalgoritmen har utvecklats i MATLAB. Utförandet av den nya skyddsalgoritmen utvärderas genom simulering av ett 500 kV två-källa kraftverk med en 200 km serie kompenserad linje i EMTDC / PSCAD (Manitoba Hydro). Den föreslagna nya skyddslösningen har visat sig vara fördelaktig.
24
Nightingale, Wendy Denise. "Electrical characteristics of an identified insect motoneurone cell body : a current- and voltage-clamp study." Thesis, University of St Andrews, 1989. http://hdl.handle.net/10023/14077.
Повний текст джерелаАнотація:
1. The electrical characteristics of the cell body of an identified excitatory motoneurone (cell 3) from the cockroach (Periplaneta americana) have been studied under current- and voltage-clamp. 2. Under voltage-clamp depolarising command pulses evoked an outward current which increased with the magnitude of the command step up to approximately +100mV, a component of the current developed more slowly and took longer to reach a maximum. With increasing depolarisation the outward current response fell to a lower level before further increasing. This current response gave rise to a characteristic N-shape I-V relationship. The position of the negative conductance region depends on the time current measurements are taken after the onset of the command pulse. 3. Externally applied cadmium (1mM) or manganese ions (5mM) abolished the slowly developing current responsible for the hump in the I-V relationship. These results indicate that calcium ions are required for the activation of this component of the outward current. Verapamil (50?M) also reduced this current component and appeared to be non-specific in reducing another current component. Furthermore, verapamil caused inactivation of the remaining current which was more marked for long duration (500ms) command pulses. 4. Externally applied TEA+ (at concentrations greater than 25mM) blocked the calcium-dependent current and a calcium-independent component. Under current-clamp TEA+ (50mM) unmasked a broad action potential. 5. Externally applied aminopyridines did not enhance excitability under current-clamp. Under voltage-clamp aminopyridines had significant effect in shifting the voltage dependence of the hump in the I-V relationship toward more negative potentials. 6. When holding at -90mV and stepping to more positive potentials there was no indication of an early, fast, transient component similar to IA. If present at all, IA made only a minor contribution to the total outward currents. 7. A double command pulse regime was used to study tail currents whereby a standard pre-pulse (pulse (I)) was immediately followed by a test pulse (pulse (II)) to various command potentials. Tail current measurements were taken during pulse (II). The tail currents showed strong outward rectification and were severely reduced in saline containing cadmium ions (ImM). 8. The tail-current reversal potential was dependent on the pulse (I) magnitude and duration. Preliminary results indicated that increasing the pulse (I) magnitude caused a negative shift in reversal potential. Increasing the pulse (I) duration from 10ms to 50ms caused a positive shift in the reversal potential equivalent to a two-fold increase in extracellular cation concentration. 9. A five-fold increase (from 3.1 to 15mM) in external potassium ion concentration produced a small and variable shift in reversal potential, which did not conform to that predicted by the Nernst equation. A five-fold decrease (from 235 to 47mM) in external chloride ion concentration had little effect on the tail current reversal potential but did cause a slight reduction in the outward currents. Furthermore, the voltage dependency of the hump in the I-V relationship was shifted toward more negative potentials. 10. Action potentials induced by intracellular citrate injection were only slightly enhanced by a four-fold increase (from 9 to 36mM) in external calcium ion concentration. They were reversibly reduced to a graded spike in saline containing verapamil (10?M) and reversibly abolished by manganese ions (40mM), but were relatively unaffected by sodium-free saline. These observations suggest that calcium ions were the major ion carrying the inward current under these conditions. 11. Carbon dioxide-induced action potentials were reversibly reduced to a graded spike in sodium-free or manganese saline (40mM) whereas tetrodotoxin (50nM) irreversibly abolished action potentials for wash period up to 20mins. These observations suggest that both calcium and sodium ions were responsible for the inward current under these conditions. 12. The regenerative component of the axotomy-induced action- potentials was reversibly reduced in sodium-free saline and only partially reduced with some broadening in calcium-free or manganese saline (40mM). Either treatment alone was insufficient to completely abolish or reduce the action potential to a graded spike. A combination of Na-free saline with manganese ions (40mM) caused a more complete block by reducing the regenerative component to a graded spike. These results suggest that sodium ions, and to a lesser extent, calcium ions were responsible for the inward current under these conditions.
25
Borzdov, A. V., V. M. Borzdov, D. V. Pozdnyakov, and F. F. Komarov. "Influence of Impact Ionization Process on Current-Voltage Characteristics of Nanoscale Silicon n-Channel MOSFET." Thesis, Sumy State University, 2013. http://essuir.sumdu.edu.ua/handle/123456789/35371.
Повний текст джерелаАнотація:
The current-voltage characteristics of nanoscale silicon n-channel MOSFET with 50 nm channel length are calculated in the present study. Both the electron and hole transport are simulated by means of the en-semble Monte Carlo method. The importance of electron impact ionization process in the transistor chan-nel for drain biases higher than 1 V is shown.
When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/35371
26
Lee, Heejae. "Analysis of Current-Voltage Hysteresis and Ageing Characteristics for CH3NH3PbI3-xClxBased Perovskite Thin Film Solar Cells." Thesis, Université Paris-Saclay (ComUE), 2018. http://www.theses.fr/2018SACLX009/document.
Повний текст джерелаАнотація:
Les perovskites organiques-inorganiques en halogénures de plomb sont des matériaux très prometteurs pour la prochaine génération de cellules solaires avec des avantages intrinsèques tels que leur faible coût de fabrication (grande disponibilité des matériaux de base et leur mise en œuvre à basse température) et leur bon rendement de conversion photovoltaïque. Cependant, les cellules solaires pérovskites sont encore instables et montrent des effets d'hystérésis courant-tension délétères. Dans cette thèse, des résultats de l’analyse physique de couches minces de pérovskite à base de CH3NH3PbI3-xClx et de cellules solaires ont été présentés. Les caractéristiques de transport électrique et les processus de vieillissement ont été étudiés avec différentes approches.Dans une première étape, la synthèse du matériau pérovskite a été optimisée en contrôlant les conditions de dépôt des films en une seule étape telles que la vitesse de rotation (6000 rpm) de la tournette et la température de recuit des films (80 °C). Dans un second temps, des cellules solaires perovskites à base de CH3NH3PbI3-xClx ont été fabriquées en utilisant la structure planaire inversée et caractérisées optiquement et électriquement.Grace à l’utilisation de la spectroscopie optique à décharge luminescente (GDOES), un déplacement des ions halogénures a été observé expérimentalement et de façon directe sous l’application d’une tension électrique. Une longueur de diffusion ionique de 140 nm et un rapport de 65% d'ions mobiles ont été déduits. Il est montré que l'hystérésis courant-tension dans l'obscurité est fortement affectée par la migration des ions halogénures provoquant un écrantage substantiel du champ électrique appliqué. Nous avons donc trouvé sous obscurité un décalage de la tension à courant nul jusque 0,25 V et un courant de fuite jusque 0,1 mA / cm2 en fonction des conditions de mesure. Grâce aux courbes courant-tension en fonction de la température, nous avons déterminé la température de transition de la conductivité ions/électrons à 260K et analysé les résultats expérimentaux en utilisant l'équation de Nernst- Einstein donnant une énergie d'activation de 0.253 eV pour les ions mobiles.Enfin, le processus de vieillissement de la cellule solaire a été étudié avec des mesures optiques et électriques. Nous avons déduit que le processus de vieillissement apparaît d'abord à la surface des cristaux de pérovskite ainsi qu’aux joints de grains. Les mesures GDOES nous indiquent que les caractéristiques électriques des cellules pérovskites sont perdues par une corrosion progressive de l'électrode supérieure en argent causée par la diffusion des ions ioduresOrganic-inorganic lead halide perovskites are very promising materials for the next generation of solar cells with intrinsic advantages such as a low-cost material due to the availability of source materials and low-temperature solution processing as well as a high power conversion efficiency of the sunlight. However, perovskite solar cells are still unstable and show deleterious current-voltage hysteresis effects. Inthis thesis, analyses of CH3NH3PbI3-xClx based perovskite thin films and solar cells are presented. The electrical transport characteristics and the ageing processes are investigated using different approaches.The synthesis of the halide perovskite materials is optimized in a first step by controlling the deposition conditions such as annealing temperature (80°C) and spinning rate (6000 rpm) in the one step-spin-casted process. CH3NH3PbI3-xClx based perovskite solar cells are then fabricated in the inverted planar structure and characterized optically and electrically in a second step.Direct experimental evidence of the motion of the halide ions under an applied voltage has been observed using glow discharge optical emission spectroscopy (GDOES). Ionic diffusion length of 140 nm and ratio of mobile iodide ions of 65 % have been deduced. It is shown that the current-voltage hysteresis in the dark is strongly affected by the halide migration which causes a substantial screening of the applied electric field. Thus we have found a shift of voltage at zero current (< 0.25 V) and a leakage current (< 0.1 mA/cm2) in the dark versus measurement condition. Through the current-voltage curves as a function of temperature we have identified the freezing temperature of the mobile iodides at 260K. Using the Nernst-Einstein equation we have deduced a value of 0.253 eV for the activation energy of the mobile ions.Finally, the ageing process of the solar cell has been investigated with optical and electrical measurements. We deduced that the ageing process appear at first at the perovskite grain surface and boundaries. The electrical characteristics are degraded through a deterioration of the silver top-electrode due to the diffusion of iodides toward the silver as shown by GDOES analysis
27
Kia, Arash. "Modeling the effects of many valley electron scattering on the current-voltage characteristics of resonant tunneling diodes /." Thesis, Connect to this title online; UW restricted, 1994. http://hdl.handle.net/1773/6060.
Повний текст джерела
28
Poláková, Simona. "Příprava perovskitových solárních článků se standardní n-i-p strukturou a jejich optimalizace." Master's thesis, Vysoké učení technické v Brně. Fakulta chemická, 2021. http://www.nusl.cz/ntk/nusl-444539.
Повний текст джерелаАнотація:
The diploma thesis deals with the study of perovskite solar cells with a regular n-i-p architecture. The theoretical part of this work is mainly focused on the stability of perovskite solar cells, i.e. thermal stability and the influence of UV radiation on final perovskite solar cell stability. Furthermore, the deposition methods, the architecture of solar cells and the materials used for the preparation of electron and hole transport layers were described in more detail. The experimental part deals with the optimization of the preparation of perovskite solar cells (especially in terms of resulting photovoltaic conversion efficiency), with a description of the structure preparation process of the final photovoltaic cell and the interpretation of the measured results.
29
Tumová, Šárka. "Vliv fotochromního aditiva na optické a elektrické vlastnosti polymerních matric." Master's thesis, Vysoké učení technické v Brně. Fakulta chemická, 2017. http://www.nusl.cz/ntk/nusl-316197.
Повний текст джерелаАнотація:
This thesis is focused on the photochromic molecule of spiropyran, which changes its structure as well as physical and chemical properties after UV irradiation. These changes are reversible, the molecule thermally restore its initial structure. For the study, the molecule SP1 with the systematic name 1',3'-dihydro-1',3',3'-trimethyl-6-nitrospiro[2H-1-benzopyran-2,2'-(2H)-indole] was used. This molecule was incorporated within polymers PVK, Tg PPV, PCBTDPP and PCDTBT and the method of UV-VIS spectroscopy was used to observe the photochromic activity within these matrices. The influence of matrices to the ability to undergo UV induced photochromic conversion as well as to the reverse conversion to the initial structure induced by heat was monitored. Furthermore, the influence of spiropyran to the electrical properties of individual matrices was studied. The effect of photochromic conversion to both, the mobility of charge carriers and to the photogeneration was observed. For this purpose, the method of current-voltage measurement was used.
30
Hills, Romilly D. Y. "Physical properties of graphene nano-devices." Thesis, Loughborough University, 2015. https://dspace.lboro.ac.uk/2134/17993.
Повний текст джерелаАнотація:
In this doctoral thesis the two dimensional material graphene has been studied in depth with particular respect to Zener tunnelling devices. From the hexagonal structure the Hamiltonian at a Dirac point was derived with the option of including an energy gap. This Hamiltonian was then used to obtain the tunnelling properties of various graphene nano-devices; the devices studied include Zener tunnelling potential barriers such as single and double graphene potential steps. A form of the Landauer formalism was obtained for graphene devices. Combined with the scattering properties of potential barriers the current and conductance was found for a wide range of graphene nano-devices. These results were then compared to recently obtained experimental results for graphene nano-ribbons, showing many similarities between nano-ribbons and infinite sheet graphene. The methods studied were then applied to materials which have been shown to possess three dimensional Dirac cones known as topological insulators. In the case of Cd3As2 the Dirac cone is asymmetrical with respect to the z-direction, the effect of this asymmetry has been discussed with comparison to the symmetrical case.
31
Modin, Emelie. "Estimating Charging on a Sounding Rocket Experiment Using Plasma Simulation." Thesis, KTH, Skolan för elektroteknik och datavetenskap (EECS), 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-293892.
Повний текст джерелаАнотація:
The aim of this project is to model current volt-age characteristic curves for different plasma conditions (i.eelectron density, electron temperature, ion temperature andplasma potential) that can be found in active auroras. This isdone by simulating the charging of a FFU with a connectedLangmuir probe in the software SPIS. These I-V curves wereused to determine the plasma properties of the auroras in whichthe sounding rockets SPIDER-1 and SPIDER-2 were launched.Through the simulations it was also studied how the differentparameters effects the I-V curves.The results showed that the plasma SPIDER-1 was launchedin most likely had properties close to nominal conditions and forSPIDER-2 there was colder electrons in the plasma. A conclusionthat only the electron temperature affects the shape of the I-Vcurves for the values simulated in this project can be drawnas well as the conclusion that the geometry of the probe doesnot affect the shape of the I-V curves. Another result showsthat electron temperature also affect how the hull of the FFUcharges. A higher electron temperature gives the hull a morenegative charge.Syftet med detta projekt är att modellera ström-pänningskaraktäristisk kurvor för olika plasmatillstånd som finns i aktiva auroror. Detta görs genom att simulera laddning på en FFU med en ansluten Langmuir-prob i SPIS. Dessa I-V-kurvor används för att bestämma plasma egenskaperna för aurororna sondraketerna SPIDER-1 och SPIDER- 2 skjöts upp i. I-V kurvorna används också för att bestämma hur plasma parametrarna elektron temperatur, jon temperatur och elektrondensitet samt hur probens geometri påverkar I-V- kurvornas utseende. Resultaten visade att den plasma SPIDER-1 blev uppskjuten i troligen hade nominella förhållanden och att den SPIDER-2 blev uppskjuten i troligtvis hade kallare elektroner. En slutsats om att endast elektron temperaturen påverkar formen på IV- kurvorna kan dras, såväl som slutsatsen att probens geometri inte påverkar formen på IV-kurvorna. Ett annat resultat visar att elektron temperaturen också påverkar ytpotentialen på FFUn. En högre elektron temperatur ger FFUn en mer negativ laddning.
Kandidatexjobb i elektroteknik 2020, KTH, Stockholm
32
Bauer, Jan [Verfasser], Ralf B. [Akademischer Betreuer] Wehrspohn, Otwin [Akademischer Betreuer] Breitenstein, and Hans-Joachim [Akademischer Betreuer] Möller. "The origins of non-ideal current-voltage characteristics of silicon solar cells / Jan Bauer. Betreuer: Ralf B. Wehrspohn ; Otwin Breitenstein ; Hans-Joachim Möller." Halle, Saale : Universitäts- und Landesbibliothek Sachsen-Anhalt, 2009. http://d-nb.info/1024937062/34.
Повний текст джерела
33
Pozdnyakov, D. V., A. V. Borzdov, and V. M. Borzdov. "Calculation of Current-Voltage Characteristics of the Optimized Triode with a Cold Cathode Based on the Ordered Array of Single-Wall Metallic Carbon Nanotubes." Thesis, Sumy State University, 2013. http://essuir.sumdu.edu.ua/handle/123456789/35361.
Повний текст джерелаАнотація:
The current-voltage characteristics of a triode with the plane-parallel electrodes and a cold cathode
based on the ordered array of single-wall metallic carbon nanotubes with open ends have been calculated
by means of a numerical solution of both the Poisson equation and the quantum-wave equation. The topological
parameters of the triode have been optimized.
When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/35361
34
Дорошенко, Дмитро Юрійович, Дмитрий Юрьевич Дорошенко, Dmytro Yuriiovych Doroshenko, Анатолій Іванович Рубан, Анатолий Иванович Рубан та Anatolii Ivanovych Ruban. "Исследование вольт-амперных характеристик и квантовой проводимости органических молекул бензол-ди-тиола и ферроцена". Thesis, Сумский государственный университет, 2014. http://essuir.sumdu.edu.ua/handle/123456789/39661.
Повний текст джерелаАнотація:
В данной работе методом разрыва перехода проведено экспериментальное исследование вольтмперных характеристик и квантовой проводимости органических молекул бензол-ди-тиола и ферроцена. В
данном случае проводился разрыв металлических золотых контактов с повторным их соединением в присутствии исследуемой молекулы. Этот принцип основан на предположении, что молекула, которая связывается с металлической поверхностью, будет с некоторой конечной вероятностью образовывать проводящий мост между электродами.
35
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.
Повний текст джерелаАнотація:
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.
36
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.
Повний текст джерелаАнотація:
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.
37
Mohammadzadeh, Saeideh. "Electronic Transport Properties of Copper and Gold at Atomic Scale." Doctoral thesis, Universitätsbibliothek Chemnitz, 2010. http://nbn-resolving.de/urn:nbn:de:bsz:ch1-qucosa-63427.
Повний текст джерелаАнотація:
The factors governing electronic transport properties of copper and gold atomic-size contacts are theoretically examined in the present work. A two-terminal conductor using crystalline electrodes is adopted. The non-equilibrium Green’s function combined with the density functional tight-binding method is employed via gDFTB simulation tool to calculate the transport at both equilibrium and non-equilibrium conditions. The crystalline orientation, length, and arrangement of electrodes have very weak influence on the electronic characteristics of the considered atomic wires. The wire width is found to be the most effective geometric aspect determining the number of conduction channels. The obtained conductance oscillation and linear current-voltage curves are interpreted. To analyze the conduction mechanism in detail, the transmission channels and their decomposition to the atomic orbitals are calculated in copper and gold single point contacts. The presented results offer a possible explanation for the relation between conduction and geometric structure. Furthermore, the results are in good agreement with available experimental and theoretical studiesIn der vorliegenden Arbeit werden die wesentlichen Faktoren, die die elektronischen Transporteigenschaften von Kontaktstrukturen atomarer Größe aus Kupfer bzw. Gold bestimmen, theoretisch untersucht. Untersuchungsgegenstand ist eine leitfähige Struktur zwischen zwei kristallinen Elektroden. Um Transportberechungen sowohl unter Gleichgewichts- als auch unter Nicht-Gleichgewichts-Bedingungen durchführen zu können, wird die Simulations-Software gDFTB, die auf dem Nicht-Gleichgewichts-Green-funktionenformalismus in Kombination mit der Dichtefunktional-Tight-Binding-Methode beruht, eingesetzt. Die elektronischen Eigenschaften der betrachteten atomaren Drähte werden nur sehr schwach von ihrer kristallinen Orientierung, ihrer Länge und der Elektrodenanordnung beeinflusst. Als effektivster geometrischer Faktor wurde der Leiterquerschnitt gefunden, weil dieser die Anzahl der Leitungskanäle bestimmt. Darüber hinaus werden die erhaltenen Leitfähigkeitsoszillationen und die linearen Strom-Spannungs-Kennlinien erklärt. Für eine detaillierte Analyse des Leitungsmechanismus werden bei den Ein-Atom-Kontakten aus Kupfer und Gold die Übertragungskanäle und ihre Aufspaltung in Atomorbitale betrachtet. Die präsentierten Ergebnisse bieten eine mögliche Erklärung für den Zusammenhang zwischen Leitfähigkeit und geometrischer Struktur. Die Resultate zeigen eine akzeptable Übereinstimmung mit den verfügbaren experimentellen und theoretischen Studien
38
Festin, Örjan. "On the Zero and Low Field Vortex Dynamics : An Experimental Study of Type-II Superconductors." Doctoral thesis, Uppsala University, Department of Engineering Sciences, 2003. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-3907.
Повний текст джерелаАнотація:
Dynamic properties of type-II superconductors have been experimentally studied in zero and low magnetic fields using SQUID magnetometry and I–V measurements.
In zero magnetic field close to the critical temperature, the physical properties of type-II superconductors are dominated by spontaneously created vortices. In three dimensions (3D) such vortices take the form of vortex loops and in two dimensions (2D) as vortex-antivortex pairs.
The 2D vortex dynamics has been probed using mutual inductance and flux noise measurements on YBa2Cu3O7 (YBCO) and MgB2 thin films in zero and low magnetic fields. In such measurements, information about vortex correlations is obtained through a temperature dependent characteristic frequency, below (above) which the vortex movements are uncorrelated (correlated). The results obtained in zero magnetic field indicate that sample heterogeneities influence the vortex physics and hinder the divergence of the vortex-antivortex correlation length.
In low magnetic fields the vortex dynamics is strongly dependent on the applied magnetic field and a power law dependence of the characteristic frequency with respect to the magnetic field is observed. The results indicate that there is a co-existence of thermally and field generated vortices.
The I–V characteristics of untwinned YBCO single crystals show that only a small broadening of the transition region influences the length scale over which the vortex movements are correlated. The dynamic and static critical exponents therefore exhibit values being larger in magnitude as compared to values predicted by relevant theoretical models. The results also suggest that the copper oxide planes in YBCO decouple slightly below the mean field critical temperature and hence, the system has a crossover from 3D to 2D behaviour as the temperature is increased.
From temperature dependent DC-magnetisation measurements performed on untwinned YBCO single crystals in weak applied fields, detailed information about the critical current density and the irreversibility line is obtained.
39
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.
Повний текст джерелаАнотація:
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.
40
Sutorý, Tomáš. "NOVÉ PRINCIPY CHARAKTERIZACE HRADLOVÝCH KAPACIT PRO SIGMA-DELTA MODULÁTORY." Doctoral thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2009. http://www.nusl.cz/ntk/nusl-233499.
Повний текст джерелаАнотація:
This thesis deals with the utilization of new principles of characterization of gate capacitances for sigma-delta modulators. Sigma-delta modulators are the integral part of sigma-delta analog-to-digital converters. The proposed new method is characterized by high resolution and modest requirements for laboratory equipment. It allows characterizing capacitances whose values are within the range which is used in sigma-delta modulators. The thesis contains description of the new method, the analysis of measurement accuracy and experimental results.
41
Щербак, Д. С. "Віртуальний лабораторний комплекс з дослідження вольт-амперних характеристик різних типів провідників". Thesis, Сумський державний університет, 2015. http://essuir.sumdu.edu.ua/handle/123456789/43377.
Повний текст джерелаАнотація:
Суть нашого проекту в створенні віртуального фізичного кабінету, який буде включати в себе набір лабораторних комплексів. Тобто, студенту надається можливість виконати будь - яку з запропонованих
лабораторних робіт не відходячи від одного робочого місця – комп’ютера, при цьому не втративши ефекту реального виконання роботи з фізики.
42
Vašíček, Michal. "Diagnostika plazmatu generovaného ve vybraných konfiguracích elektrického výboje v kapalném prostředí." Master's thesis, Vysoké učení technické v Brně. Fakulta chemická, 2014. http://www.nusl.cz/ntk/nusl-217023.
Повний текст джерелаАнотація:
My diploma thesis is focused on a comparison of direct-current and high frequency (15-80 kHz) electric discharge, which generates non-thermal plasma in water solution of sodium chloride. Mainly current-voltage and Lissajous charts are discussed in the first part of this thesis. These charts describe different discharge phases: electrolysis, bubble formation, discharge breakdown and discharge regular operation in a pin-hole of a dielectric barrier. Influence of frequency, electrolyte conductivity, thickness of the diaphragm (or length of the capillary) and pin-hole diameter on discharge breakdown and bubble generation was studied, too. Measurements were realized in a polycarbonate reactor with total volume of 110 ml, which was divided by a changeable polyacetal insulating wall. This wall divided the reactor into two approximately equal spaces with one stainless steel planar electrode in each part. The Shapal-MTM ceramic discs (thickness of 0.3–1.5 mm and diameter of the central pin-hole of 0.3-0.9 mm) were mounted in the centre of the insulating wall. Initial conductivity of sodium chloride solution was chosen within the interval of 100900 S/cm. The second part of my thesis compares an influence of the direct-current (DC) and high frequency (HF) power sources on physical solution properties (conductivity, pH and temperature) and generation of hydrogen peroxide. A plasma reactor with total volume of 4 l and with mixing set up was divided into two equal spaces with one planar platinum electrode in each part. Diaphragm with thickness of 0.6 mm and pin-hole diameter of 0.6 mm was installed in the middle of the separating wall. Experiment was held at discharge operation of 45 W for 40 minutes with both power sources. Detection of hydrogen peroxide was realised by using a titanium reagent forming a yellow complex, which was analysed by absorption spectroscopy. If HF discharge power is plotted as a function of applied frequency, exponential decrease of frequency with increasing power can be observed. Higher breakdown voltage is necessary for thicker dielectric barriers, on the other hand for bigger diameter of the pin-hole lower breakdown voltage and higher power is needed in DC as well as in HF regime. Breakdown voltage is decreased by the increasing conductivity in both regimes; due to more charge carriers in the higher conductivity lower breakdown voltage is needed. However frequency in HF regime and DC discharge power increases. HF discharge power is decreased by the increasing conductivity. Solution conductivity and temperature are increased by initial conductivity value in both discharge regimes. Solution pH drops to acidic conditions when HF or DC positive regime is applied due to the generation of reactive species and electrolysis (in DC regime). However solution becomes alkaline when DC negative regime is applied. Concentration of hydrogen peroxide is produced linearly when HF or DC negative regime is applied and it depends on initial solution conductivity.
43
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.
Повний текст джерелаАнотація:
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.
44
Gorge, Vanessa. "Caractérisations de matériaux et tests de composants des cellules solaires à base des nitrures des éléments III-V." Phd thesis, Université Paris Sud - Paris XI, 2012. http://tel.archives-ouvertes.fr/tel-00707717.
Повний текст джерелаАнотація:
Parmi les nitrures III-V, le matériau InGaN a été intensément étudié depuis les années 2000 pour des applications photovoltaïques, en particulier pour des cellules multi-jonctions, grâce à son large gap modulable pouvant couvrir quasiment tout le spectre solaire. On pourrait alors atteindre de hauts rendements tout en assurant de bas coûts. Cependant, l'un des problèmes de l'InGaN est l'absence de substrat accordé en maille provoquant une grande densité de défauts et limitant ainsi les performances des composants. Nous avons donc étudié la faisabilité de cellules solaires simples jonctions à base d'InGaN sur des substrats alternatifs comme le silicium et le verre afin de baisser les coûts et d'avoir de larges applications. Afin d'adapter l'InGaN sur ces substrats alternatifs, nous avons utilisé une couche tampon en ZnO. Ce travail a été réalisé dans le cadre du projet ANR NewPVonGlass. Plus particulièrement, dans ce projet, mon travail avait pour objectifs de réaliser des caractérisations électriques et optiques des matériaux et des composants. Les deux premières parties de cette thèse introduisent le matériau InGaN et l'effet photovoltaïque. Les techniques de caractérisation utilisées sont expliquées dans le troisième chapitre. Ensuite, les résultats obtenus lors de la caractérisation cristalline du matériau InGaN sont présentés en fonction du substrat, de la concentration d'indium et de l'épaisseur de la couche. Puis, la cinquième partie développe les caractérisations des premières cellules à base d'InGaN sur saphir. Enfin, dans le dernier chapitre, des simulations de cellules solaires à base d'InGaN ont été réalisées. Le modèle développé nous a permis d'optimiser la structure et le dopage du composant et de déterminer les paramètres critiques. Nous montrons donc, dans ce travail, le développement d'une cellule solaire à base d'InGaN : des caractérisations des matériaux de base à celles des cellules solaires, en passant par la modélisation.
45
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.
Повний текст джерелаАнотація:
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.
46
Carbonell, Cortés Carla. "Customizing a low temperature system for microwave transmission measurements. Quantum transport in thin TiN films and nanostructures." Doctoral thesis, Universitat de Barcelona, 2012. http://hdl.handle.net/10803/83635.
Повний текст джерелаАнотація:
The work presented in this thesis consists of two distinct parts.
The first years of my work focused on the development and improvement of a new equipment built to study magnetic and electrical properties, particularly applying microwaves in reflection and transmission conditions. The sample space in conventional cryostats with superconducting magnets is usually smaller than 10-mm-diameter. Our equipment consists of a hollow cylindrical cryostat having a 33-mm-diameter hole all along its vertical axis. These characteristics enable the measurement of large samples and the use of big resonant cavities to get to a wider microwave (MW) range, particularly in transmission measurements.
The cryostat has a superconducting magnet made of a solenoid that applies a magnetic field from -5 T to 5 T, and a temperature controller that works in the range 1.8 - 300 K. The system is cooled down with nitrogen and helium and the temperature can be controlled with the precision required by each experiment using a heater and a needle valve.
Different probes for a wide range of experiments in our cryostat have been developed in order to be as versatile as possible. Following this idea each one has been divided in two halves that can be combined as it is preferred in each experiment. Each probe is made of a 8-to-10-mm-diameter stainless steel tube that is used to protect and give some stiffness to the measuring device. A coaxial cable and different waveguides are added to these stainless steel jackets, so we end up having nine halves, four upper parts that can be combined with five lower parts. There are three waveguides working in the frequency ranges 33-50 GHz (WR22), 50-75 GHz (WR15) and 75-110 GHz (WR10), and a coaxial cable that maintains the fundamental mode at a frequency of 60 GHz. In the extra lower part a 16-pin Fischer connector is added at the bottom in order to be able to perform more resistance experiments. Once the probes have been built, they have been tested to make sure the system is able to reach high vacuum and to be cooled down. Problems found along the way have been solved and at the end all the probes work properly.
Different sample holders have been designed and built according to the needs in each experiment. The system has been tested by reproducing experimental results with Mn12-acetate, as quantum tunneling and magnetic avalanches, and by obtaining new results on microwave transmission in thin TiN films.
The second part of the thesis focuses on the measurements of thin TiN films in a dilution refrigerator working with a mixture of 3He and 4He that enables experiments at a few tens of millikelvins. The cryostat also contains a superconductor magnet which can apply a magnetic field up to 5 T.
Low-temperature transport properties of nanoperforated superconducting TiN films have been experimentally studied. Resistance measurements have been performed in the critical region of the superconductor-insulator transition (SIT), applying the magnetic field perpendicular to the plane of the structure or the dc current through the sample.
SIT is a transition from a superconductor to an insulator state by localizing the Cooper pairs. The evolution of the SIT with temperature, magnetic field and dc current has been investigated in detail.
Characteristic parameters have been determined for as-cast thin films using the theory of quantum corrections to conductivity. Disorder-driven and field-induced SITs have been measured. Commensurability effects have been observed down to the lowest experimental temperature, and are emphasized in the more disordered samples. The SIT has been observed for a dc current applied across the sample as changes in the curvature at zero bias current. Experiments prove that electronic transport in the nanoperforated samples is mediated by Andreev conversion. Finally, the existence of the superinsulator state has been experimentally proved.El treball que es presenta en aquesta tesi consta de dues parts ben diferenciades. La primera pretén el desenvolupament d’un equip experimental concebut per a l’estudi de propietats magnètiques i elèctriques en materials diversos i, en especial, el treball amb radiació de microones en condicions de reflexió i transmissió. La segona s’ha centrat en les mesures de transport d’una capa fina superconductora de nitrur de titani (TiN) de 5 nm de gruix en un criòstat de dilució.
47
Ahmed, Mustafa M. Abdalla. "Alternating-Current Thin-Film Electroluminescent Device Characterization." Doctoral thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2008. http://www.nusl.cz/ntk/nusl-233432.
Повний текст джерелаАнотація:
Jádrem této disertační práce bylo studovat optické a elektrické charakteristiky tenkovrstvých elektroluminiscenčních součástek řízených střídavým proudem (ACTFEL) a zejména vliv procesu stárnutí luminiforů na jejich optické a elektrické vlastnosti. Cílem této studie měl být příspěvek ke zvýšení celkové účinnosti luminoforů, vyjádřené pomocí jasu, účinnosti a stability. Vzhledem k tomu, že současnou dominantní technologií plochých obrazovek je LCD, musí se další alternativní technologie plošných displejů porovnávat s LCD. Výhodou ACTFEL displejů proti LCD je lepší rozlišení, větší teplotní rozsah činnosti, větší čtecí úhel, či možnost čtení při mnohem vyšší intenzitě pozadí. Na druhou stranu je jejich nevýhodou vyšší energetická náročnost, problém s odpovídající barevností tří základních barev a podstatně vyšší napětí nutné pro činnost displeje. K dosažení tohoto cíle jsme provedli optická, elektrická a optoelektrická měření ACTFEL struktur a ZnS:Mn luminoforů. Navíc jsme studovali vliv dotování vrstvy pomocí KCl na chování mikrostruktury a na elektroluminiscenční vlastnosti (zejména na jas a světelnou účinnost) ZnS:Mn luminoforů. Provedli jsme i některá, ne zcela obvyklá, měření ACTFEL součástek. Vypočítali jsme i rozptylový poměr nabitých barevných center a simulovali transportní charakteristiky v ACTFEL součástkách. Studovali jsme vliv stárnutí dvou typů ZnS:Mn luminoforů (s vrstvou napařenou či získanou pomocí epitaxe atomových vrstev) monitorováním závislostí svítivost-napětí (L-V), velikost vnitřního náboje - elektrické pole luminoforu (Q-Fp) a kapacitance-napětí (C-V) ve zvolených časových intervalech v průběhu stárnutí. Provedli jsme krátkodobá i dlouhodobá měření a pokusili jsme se i o vizualizaci struktury luminoforu se subvlnovým rozlišením pomocí optického rastrovacího mikroskopu pracujícího v blízkém poli (SNOM). Na praktickém případu zeleného Zn2GeO4:Mn (2% Mn) ACTFEL displeje, pracujícího při 50 Hz, jsme také studovali stabilitu svítivosti pomocí měření závislosti svítivosti na napětí (L-V) a světelné účinnosti na napětí (eta-V). Přitom byl zhodnocen význam těchto charakteristik. Nezanedbatelnou a neoddělitelnou součástí této práce je i její pedagogický aspekt. Předložený text by mohl být využit i jako učebnice pro studenty na mé univerzitě v Lybii.
48
Dubois, Diane. "Réalisation et caractérisation d'un réacteur plasma de laboratoire pour des études sur la dépollution des gaz d"échappement." Toulouse 3, 2006. http://www.theses.fr/2006TOU30139.
Повний текст джерелаАнотація:
Cette thèse concerne l’étude expérimentale des décharges couronne positives à la pression atmosphérique générées dans un réacteur de laboratoire de type pointe – plan alimenté en régime de tension continue et pulsée. La nature et les caractéristiques de la décharge couronne, notamment dans son régime de « breakdown streamer », sont étudiées en fonction du régime et de l’amplitude de l’alimentation de tension, du rayon de courbure de la pointe, de la distance inter – électrodes ou encore de la composition du mélange gazeux en faisant varier les proportions de N2, de O2 et de CO2. La dynamique et la morphologie des ondes d’ionisation sont finement étudiées à l’aide de diagnostics d’imagerie rapide (ICCD Streak caméras) et de mesures instantanées de courant et de tension (oscilloscope rapide) sur des échelles de temps de quelques centaines de nanosecondes. Les dimensions du réacteur ont été adaptées à la capacité des modèles à le simuler et les premiers résultats de comparaison des courbes instantanées de courant issues des modèles et de l’expérience sont présentés dans le but ultérieure d’estimer la nature et la densité des radicaux formés durant la phase de décharge d’un réacteur de dépollution par décharge couronneThe present thesis is devoted to the experimental study of atmospheric positive corona discharges generated in a point to plane corona reactor under DC or pulsed high voltage conditions. The corona discharge characteristics, in particular during “breakdown streamer” mode, are studied according to the high voltage supply conditions (DC or pulsed), the point radius curvature, the gap distance or the gas mixture following the variation of the N2, O2 and CO2 concentration. The dynamics and the morphology of the streamers are also studied using fast imaging (ICCD and Streak cameras) and electrical (oscilloscope) diagnostics on time scale lower than hundred of nanosecond. As the corona discharge reactor dimensions are well adapted, some preliminary results show the comparison between experimental and simulated results which allow us in the future to estimate the localization, the density and the nature of the radical species created during the discharge phase of a corona reactor devoted to air pollution control
49
Dřímalková, Lucie. "Diagnostika diafragmového výboje ve vodných roztocích a jeho aplikace pro povrchovou úpravu nanomateriálů." Doctoral thesis, Vysoké učení technické v Brně. Fakulta chemická, 2019. http://www.nusl.cz/ntk/nusl-402110.
Повний текст джерелаАнотація:
The exact mechanism of the discharge in liquids ignition is not sufficiently known up to now. Although during the last years was achieved the great progress and overloading which some of them are written in this theoretical part of thesis. This thesis is divided into two experimental parts. When the first part deals with diagnostics of diaphragm discharge in electrolyte solutions and the second part is focused on its use for uncoiling (higher homogenization) of carbon nanotubes in solutions. In experiment 1, three different sized (4 l, 100 ml, 50 ml) diaphragm discharge configurations were used to diagnose diaphragm discharge in electrolyte solutions. Diagnostics is done through current and voltage waveforms with the addition of synchronized ICCD camera images that have been connected to a four-channel oscilloscope. The V-A characteristic can be described by three events occurring in the electrolyte solution with a gradual increase in voltage. Slowly increasing of the voltage in the solution leads first to electrolysis. The next phase is the formation of microbubbles or bubbles, which is characteristic of the curve by a slight decrease in the increase of the current passing between electrodes. The sudden increase in the current flow is characteristic of the last phase, namely the discharge phase. The distance of the electrodes from the diaphragm does not significantly affect the V-A characteristic. The higher diameter of the pin hole, therefore, has a higher voltage, but this does not affect the origin of bubble generation or breakdown. The higher thickness of diaphragm, the higher voltage is needed to the beginning of the bubbles generation, and consequently the discharge breakdown. Comparison of the voltage of the start generation of the bubbles and breakdown for PET diaphragms and diaphragms from the ceramic there was no mark able difference. One of the most important parameters is the conductivity of the electrolyte solution. The lower voltage is needed for the start generation of the bubbles at the higher solution conductivity, and also the discharge generation is observed at a lower breakdown voltage. The second experimental part is focused on the study of the diaphragm discharge effect on carbon nanotubes. A specially designed U-shaped reactor is used to modify carbon nanoparticles. Tap water and aqueous solutions of organic compounds are used as the electrolytic solutions. The discharge is generated by a non-pulsed DC high source with a voltage in the range of 0-2.8 kV supplied to platinum electrodes located in the electrolyte solution. The experimental results have shown that the diaphragm discharge has positive effects on the disintegration of clusters and agglomerates of carbon nanotubes. The primary effect on disintegration is probably the shock waves generated by the discharge. It turned out that it depends on the electrode configuration, where the treatment in anode space has far greater effects than the treatment in cathode half of the reactor. Effects of carbon nanotubes disintegration in solution are long-lasting and the treatment effect is not loosed after several months. There were detected no significant changes in the structure of plasma-treated nanotubes by Infra-red spectroscopy.
50
Pokorný, Marek. "Charakterizace vlastností fotovoltaického systému." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2011. http://www.nusl.cz/ntk/nusl-219073.
Повний текст джерелаАнотація:
The aim of this work is informed first about photovoltaics universally, works to inform the photovoltaic panels and complete plants. The work also includes instructions on how to implement PVP in accordance with law. Another part is the rough draft of the photovoltaic power 30 kWp, which can be placed on the house, computation and calculation of investment and them profitable investments to time. Design is made in two separate forms of the Fronius Solar and Sunny Design, their outputs are compared. The practical part of this work cooperates with the company SOLARTEC Ltd. for experimental measurements of the photovoltaic system and develop a methodology for setting the properties of real solar systems in operation from the measured data then stored in a database. These data further evaluate and compare the similar operating conditions. This data will show as the course of production of electricity during the typical day in percentage terms, depending on the incident irradiance, cell temperature, angle of incident radiation, etc. We can compare what it looks like an ideal day in terms of production of photovoltaic power, with the other days. Further are in work mentioned histograms achievement panel behind classical day and behind all - time investigation.