Tesis sobre el tema "Electric field intensity"
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Goulart, Jair Trapé 1987. "Vulnerabilidade de miócitos cardíacos a campos elétricos de alta intensidade = influência da estimulação beta-adrenérgica = The lethal effect of high-intensity electric fields on cardiac myocytes: influence of the beta-adrenergic pathway". [s.n.], 2012. http://repositorio.unicamp.br/jspui/handle/REPOSIP/259400.
Texto completoDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Elétrica e de Computação
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Resumo: A aplicação de campos elétricos de alta intensidade (CEAI) no coração é realizada frequentemente durante tentativas de reversão da fibrilação, e para gerar sincronismo cardíaco com o uso de marca-passos. Entretanto, este procedimento rotineiro pode causar danos ao miocárdio. O objetivo deste trabalho foi investigar se a estimulação ?-adrenérgica afeta a vulnerabilidade de miócitos ventriculares ao CEAI, uma vez que, durante a fibrilação ventricular, há aumento reflexo do tônus simpático, em virtude da consequente hipotensão arterial, e a administração de catecolaminas é um procedimento comum neste tipo de emergência. Miócitos foram isolados do ventrículo esquerdo de ratos Wistar adultos por digestão enzimática. As células foram perfundidas com solução de Tyrode a 23 °C e estimuladas a 0,5 Hz. Aplicou-se CEAI em intensidades crescentes até que fosse induzida uma lesão letal na célula. A probabilidade de morte celular foi determinada em função da amplitude do CEIA e da máxima variação estimada do potencial de membrana (?Vmax) por análise de sobrevivência (curva de letalidade). Destas curvas, obteve-se o parâmetro EL50 (valor de CEAI ou ?Vmax com probabilidade de letalidade de 0,5). A estimulação ?-adrenérgica, pela perfusão com 10 nM de isoproterenol (ISO), foi realizada na ausência e presença de 150 nM de metoprolol (MET, bloqueador de adrenoceptores ?1), 10 ?M de H-89 (inibidor de PKA) e 500 nM de BIS I (inibidor de PKC), bem como após protocolo para minimizar o aumento de mobilização celular de Ca2+. As curvas foram comparadas por teste de Mantel-Cox. O tratamento com ISO promoveu o deslocamento da curva para a direita (p < 0,01) e EL50 aumentou de 85 para 100 V/cm. MET e H-89 aboliram o efeito protetor do ISO, e, quando perfundidos na ausência de ISO, não tiveram quaisquer efeitos sobre a indução de letalidade por CEAI. A redução da mobilização de Ca2+ e o tratamento com BIS I não alteraram as curvas de letalidade, na presença ou ausência de ISO, mas provocaram significante aumento no tempo de recuperação das células após um choque não letal. As curvas em função de ?Vmax foram similares àquelas em função da intensidade do campo. Os resultados mostram que a estimulação ?-adrenérgica é capaz de proteger os miócitos dos efeitos deletérios do CEAI, permitindo que a célula suporte maiores ?Vmax. A proteção parece ser mediada por adrenoceptores ?1 e PKA, e possivelmente envolve ativação de mecanismos de reparo. Estas vias de proteção podem ser futuramente exploradas para atenuar os danos miocárdicos causados pela desfibrilação/cardioversão
Abstract: The myocardium is exposed to high-intensity electric fields (HIEF) during cardiac electric defibrillation, which may reverse life-threatening arrhythmias, but also cause cell damage. Impairment of cardiac pumping during ventricular fibrillation is usually associated with high sympathetic tone, and catecholamine infusion is a common procedure for the emergencial treatment of this arrhyhmia. The present study was carried out to investigate whether adrenergic stimulation affects the vulnerability of ventricular myocytes to the lethal effect of HIEF. Left ventricular myocytes were isolated from adult Wistar rat hearts by collagenase digestion. Under perfusion with Tyrode's solution at 23 ºC, cyclic contractile activity was evoked by stimulation at 0.5 Hz. A HIEF pulse was then applied, after which cells were allowed to rest and recover from the shock. Afterward, the protocol was repeated increasing HIEF amplitude until cell death ensued. The probability of cell death as a function of the field intensity or the estimated maximum change in membrane potential, ?Vmax (lethality curve) was determined by survival analysis. The protocol was carried out during exposure to 10 nM isoproternol (ISO), in the absence and presence of the ?1-adrenoceptor blocker metoprolol (MET, 150 nM), the PKA inhibitor H-89 (10 ?M), the PKC inhibitor BIS I (500 nM), or after a protocol designed to attenuate the increase in cell Ca2+ mobilization by ISO. Lethality curves were compared with the Mantel-Cox test. Exposure to ISO produced a marked rightward shift of the lethality curves (p< 0.01), and the field intensity associated with the cell death probability of 0.5 (EL50) was increased from 85 to 100 V/cm. Treatment with MET or H-89 alone did not significantly affect the curves, but completely abolished ISO protective effect. Decreasing Ca2+ mobilization and BIS I treatment did not produce significant effects on the lethality curves, either in the absence or presence of ISO, but they increased the time spent to cell recovery after a non-lethal shock. Similar results were obtained for the lethality curve as a function of ?Vmax. Therefore, ?-adrenergic stimulation confers protection to ventricular myocytes from the lethal effects of HIEF, even though cells apparently experience higher variations of ?Vmax, which should lead to extensive electroporation. This effect, which seems to be mediated by ?1-adrenoceptors and dependent on PKA activation, possibly involving recruitment of membrane repair mechanisms. This protective effect may be further explored as a means to attenuate HIEF deleterious effects on cardiac function that frequently result from electric defibrillation/cardioversion
Mestrado
Engenharia Biomedica
Mestre em Engenharia Elétrica
Hermany, Jiří. "Záření soustav antén v blízké zóně". Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2008. http://www.nusl.cz/ntk/nusl-217536.
Texto completoТкаленко, Р. Г. "Чисельне моделювання аксіально-симетричних електронних потоків у НВЧ приладах типу ЛБХ". Master's thesis, Сумський державний університет, 2019. http://essuir.sumdu.edu.ua/handle/123456789/73319.
Texto completoHarvey, Christopher. "Electron dynamics in high-intensity laser fields". Thesis, University of Plymouth, 2010. http://hdl.handle.net/10026.1/301.
Texto completoJennings, Jessica Amber. "Regulation of gene expression in response to continuous low Intensity direct current electrical fields". Birmingham, Ala. : University of Alabama at Birmingham, 2007. https://www.mhsl.uab.edu/dt/2009r/jennings.pdf.
Texto completoAdditional advisors: Susan Bellis, Vladimir Fast, Chi-Tsou Huang, Donald Muccio. Description based on contents viewed June 23, 2009; title from PDF t.p. Includes bibliographical references.
Hangya, Josef. "Účinky elektrického namáhání na vlastnosti elektroizolačních materiálů". Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2014. http://www.nusl.cz/ntk/nusl-220958.
Texto completoSánchez, Vega Rogelio. "Effects of high-intensity pulsed electric fields on the bioactive compounds stability and enzymes of broccoli juice". Doctoral thesis, Universitat de Lleida, 2016. http://hdl.handle.net/10803/383050.
Texto completoLa presente tesis doctoral se centro en evaluar la influencia de los paramétros de procesamiento de HIPEF (intensidad de campo eléctrico, tiempo de tratamiento y polaridad) sobre los compuestos bioactivos (clorofilas, carotenoides, vitamina C y compuestos fenólicos totales), minerales, aminoácidos y enzimas (mirosinasa, polifenol oxidasa y lipoxigenasa) de zumo de brócoli. Los resultados del zumo de brócoli procesado con HIPEF fueron comparados con aquellos del zumo tratado térmicamente (90 °C/60 s) y del zumo sin procesar. Las parámetros de procesamiento con HIPEF influyó significativamente sobre el contenido relativo (RC) de luteína, β-caroteno, fenoles totales (TP), vitamina C, minerales y aminoácidos, capacidad antioxidante relativa, así como el RC de compuestos de degradación de clorofila, las enzimas clorofilasa, polifenol oxidasa, lipoxigenasa y diferencia de color (ΔE). Sin embargo, la polaridad no tuvo influencia sobre Chl a, Chl b ni sobre ΔE. El zumo de brócoli tratado con HIPEF mostró un mayor contenido de clorofilas, carotenoides, TP, vitamina C, minerales, aminoácids, y capacidad antioxidante que aquellos procesados térmicamente y sin tratar. Además, la ΔE más elevada (7.89) fue observada en el zumo de brócoli procesado con calor.
La present tesi doctoral es va centrar en avaluar la influència dels paràmetres de processament de HIPEF (intensitat de camp elèctric, temps de tractament i polaritat) sobre els compostos bioactius (clorofil•les, carotenoides, vitamina C i compostos fenòlics totals), minerals, aminoàcids i enzims (mirosinasa, polifenol oxidasa i lipoxigenasa) de suc de bròquil. Els resultats del suc de bròquil processat amb HIPEF van ser comparats amb aquells del suc tractat tèrmicament (90 °C/60 s) i del suc sense processar. Les paràmetres de processament amb HIPEF va influir significativament sobre el contingut relatiu (RC) de luteïna, β-carotè, fenols totals (TP), vitamina C, minerals i aminoàcids, capacitat antioxidant relativa, així com el RC de compostos de degradació de clorofil•la, els enzims clorofilasa, polifenol oxidasa, lipoxigenasa i diferència de color (ΔE). No obstant això, la polaritat no va tenir influència sobre Chl a, Chl b ni sobre ΔE. El suc de bròquil tractat amb HIPEF va mostrar un major contingut de clorofil•les, carotenoides, TP, vitamina C, minerals, aminoácids, i capacitat antioxidant que aquells processats tèrmicament i sense tractar. A més, la ΔE més elevada (7.89) va ser observada en el suc de bròquil processat amb calor.
Cameron, Douglas Gordon. "Studies on the use of high intensity pulsed electric fields for the inactivation of problematic food-borne microorganisms". Thesis, University of Strathclyde, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.401574.
Texto completoMorozionkov, Jevgenij. "Pramoninio dažnio elektromagnetinių laukų tyrimas". Master's thesis, Lithuanian Academic Libraries Network (LABT), 2006. http://vddb.library.lt/obj/LT-eLABa-0001:E.02~2006~D_20060613_110343-33965.
Texto completoAlmousa, Almaksour Khaled. "Etude de l’émission cathodique sous vide en présence d'un champ électrique intense et des paramètres physiques gouvernant son intensité". Thesis, Paris 11, 2014. http://www.theses.fr/2014PA112017/document.
Texto completoField electronic emission is a domain which concerns numerous different technical applications. In this work, we have taken an essentially experimental approach to study various parameters having influence on field emission. In the first part of the thesis, we have described the results obtained with a homogeneous electric field with relatively weak field emission. The role of the inter-electrode distance at constants field as well as that of the cathode surface roughness on field emission are studied. The classical method of Fowler-Norheim was then used for the analysis of the measurements. A simple model aiming to take into account the effect of the heating of the emission sites is then proposed. The second part of the theses concerns the effect of the injection of gas on the field emission; this effect being to significantly reduce emission intensity when the gas pressure is raised from 10⁻⁶ to 10⁻² Pa at constant field. A threshold value of emission intensity is shown to be necessary for the observation of this gas effect. The effect of different gas types (He, H₂, N₂, Ar) and cathode materials are also described. The gas effect is shown to be reversible upon lowering of the gas pressure to 10⁻⁵ Pa. The reduction in current is interpreted by a lowering of the field enhancement factor (β) of emission sites by ionic bombardment by ions created locally (within distances on the order of microns) near the cathode surface. A calculation of the flux of bombarding ions is used to estimate the time necessary to modify an emission site in a way corresponding to the observations. The phenomenon of surface migration in the presence of intense electric field is then proposed to explain the reversibility of the gas effect, increasing the local field enhancement factor
Kuprusevičius, Vaidas. "Transformatorinių pastočių skleidžiamų elektromagnetinių laukų tyrimas". Master's thesis, Lithuanian Academic Libraries Network (LABT), 2010. http://vddb.laba.lt/obj/LT-eLABa-0001:E.02~2010~D_20100618_134150-69461.
Texto completoLiterary review, according to theoretical and experimental researches, it was noticed that electromagnetic fields of industrial frequency influence the human and environment. The most sensitive parts to the effect of electromagnetic fields are the nervous system and the neuroendocrine system. The biggest sources of electromagnetic fields are the domestic appliances, the installations of electricity transmission, transference and the distributing installations in residential and working places. Electromagnetic fields are generated with electric installations and spread in space by 1/r3; 1/r2 and 1/r law. It is typical of the value change of electric and magnetic fields. Parameter value of electromagnetic fields is solved with electricity installations tension, stream and the location of analyzed point in point of installations. Summing up the wide energetic net of our country, the fact of usable electric installations (which create electromagnetic fields in residential and working places) assume the marked social signification, there is posed the opportunity to forecast the available values of low electromagnetic fields effect, and to forecast means to remove it.
Soueid, Malak. "Contribution au développement et à la caractérisation d’applicateurs pour les études bioélectromagnétiques portant sur les ondes radiofréquences et les impulsions électriques nanosecondes de haute intensité". Thesis, Limoges, 2016. http://www.theses.fr/2016LIMO0081/document.
Texto completoIn this thesis, we propose and study exposure systems to explore healthy and therapeutic biological effects of EM signals. We propose a microwave antenna for thermal ablation of liver tumors at 2.45 GHz. Its original feature consists in its reduced dimensions that permits the endoscopic insertion in the zone to be treated. For this antenna, a specific absorption rate (SAR) greater than 50 W/kg/W inc showed an exposed zone of 1-cm diameter. We propose a transverse electromagnetic cell (TEM) with an aperture sealed with a transparent conducting material Indium tin oxide (ITO).This TEM cell can be used to study the potential effects of wireless communication systems on biological cells. This delivery device allows real-time observation of biological cells during exposure across the aperture sealed with ITO. The effect of the aperture and the ITO layer presence on the SAR in the exposed sample was evaluated. The SAR values obtained at 1.8 GHz in the sample exposed in the TEM cell with the sealed or non-sealed aperture of 20-mm diameter were 1.1 W/kg/W inc and 23.6 W/kg/W inc, respectively. An excellent homogeneity of SAR was achieved in the medium in the presenceof ITO. Finally, we propose several devices for the exposure of biological medium to nanosecond pulsed electric field with high intensity (nsPEFs). The biological effect of nsPEFs are used in biotechnology and medicine. We propose two devices with electrodes in direct contact with the biological medium and three devices with isolated electrodes. We demonstrate their adaptation for 3-ns duration pulses and the suitability of those with electrodes in contactwith the biological medium to provide high intensities fields in the order of several MV/m. We demonstrate the importance of the isolated devices for delivering ultrashort pulses
Ho, Sheng-Hao y 何晟豪. "Simulating and Analyzing the Intensity of the Electric-field in an RFID Portal". Thesis, 2013. http://ndltd.ncl.edu.tw/handle/xj8bhb.
Texto completo國立臺北科技大學
製造科技研究所
101
When RFID technology was bringing in business company, the first problem that we might face is how to contain the stability of RFID tag’s read-rate. Due to so many interferences, such as environment, tag’s positions, antenna’s gain ability and design…etc, all interferences could cause the read-rate declining. If we can build a way to setup the antenna’s parameter, and remove the interferences of RFID read-rate, we must could increase more benefit of this technology. My research is talked about how to use the simulation software—HFSS(built by Ansoft Co.) to adjust the RFID portal, and to increase the read-rate stability(when high quantity tags in). Then we use experiments and simulations to make a standard way to adjust RFID portal, and help the RFID portal users to utilize simply and standardly.
Koehler, Robert. "Intensity error sensing in the active control of free field sound radiation / Robert Keohler". 2001. http://hdl.handle.net/2440/21780.
Texto completoBibliography: p. 285-310.
xlvi, 350 p. : ill. (some col.), plates (col.) ; 30 cm.
Title page, contents and abstract only. The complete thesis in print form is available from the University Library.
This thesis describes by theory and experiment, the effectiveness of an alternate error sensing strategy suitable for the control of general free field sound radiation problems, namely active intensity. In this research, active intensity error sensing has been rigorously analysed: 1. in the near and far field of the disturbance source; 2. to determine its ability to lead to global control via sound power attenuation; 3. in a real control system. The performance of active intensity error sensors were evaluated both analytically and experimentally in progressively more complex environments to identify their capabilities and limitations.
Thesis (Ph.D.)--University of Adelaide, Dept. of Mechanical Engineering, 2001
Fu, Chien-Hua y 傅建樺. "Analysis of electric field intensity between zero-potential and charged conductors in insulation oil". Thesis, 2011. http://ndltd.ncl.edu.tw/handle/y9jtuz.
Texto completo中原大學
電機工程研究所
99
It is necessary to consider the electric field intensity between zero-potential and charged conductors when designing the interior of a transformer. When the interior intensity of a transformer exceeds the maximum limit, the insulation will be destroyed and the life-span of the transformer will be reduced. This technical report addresses this problem to ensure the security of a transformer usage and reduce the design cost. It is expected to know the interior of a transformer detailedly.
Wang, Wei-Hsin y 王偉欣. "Effect of the Design of Wire Electrode and Process Parameters on the Electric Field Intensity of Polypropylene Electret Nonwoven Fabric". Thesis, 2002. http://ndltd.ncl.edu.tw/handle/8sbub8.
Texto completo逢甲大學
紡織工程所
90
As the improvement of the technology and the living quality, the high performance filters have been a necessity for the industrial and the consumer product. Recently, the quantity of the filter made by the non-woven material is increased day by day. The consuming volume of the non-woven material made by the organic synthesis fiber for the air filtration is increasing steadily also. The main topic for this research is focused on the influence about the charging capability carried by the modified wire electrode and the capability of keeping the electrostatic voltage carried of the electret made by polypropylene melt-blow nonwoven fabric. The process parameters in the experiment are design of the electrode, electric field intensity of the charge( 167 kV/m, 333 kV/m, 500 kV/m, 667 kV/m), heating temperature (30~35 0C, 50~55 0C, 70~75 0C), cooling temperature( 23 0C, 15 0C, 10 0C, 5 0C, 0 0C, -5 0C) and the distance between the electrodes (70 mm, 140 mm, 210 mm). In order to increase the charging ability of the electret, we install a 165 W UV lamp at the position before the area of elimination of electrostatic voltage in the machine for the purpose of the initiation of the material by the exposure of light. Besides, the capability of the charging and keeping of the electricity of the electret can be improved by the installation of heating equipment before the electrode area of the machine and the cooling equipment in the area of the electrodes located. From the result of this experiment, we found the stronger intensity of the surface electrical field of the electret can be got is under the situation when the charged intensity reaches 500 kV/m when we use 100 μm golden wire electrode as the material for the wire electrode and pick up the copper pipe with 10 mm radius for this research. This combination will lower the interference of the electric field intensity between the electrodes. The best condition for the charging efficiently of the electricity into the electret is to assign the heating temperature around 50~55 0C and the cooling temperature as 150C respectively. The charging space of the machine can be reduced by the choice the copper— pipe electrode, because the intensity of the charging field will not be influenced when the distance between the electrodes becoming smaller.
Chou, Jung-Feng y 周榮峯. "Effect of the Design of Needle Electrode and Process Parameters on the Electric Field Intensity of Polypropylene Electret Nonwoven Fabric". Thesis, 2002. http://ndltd.ncl.edu.tw/handle/vk4j9k.
Texto completo逢甲大學
紡織工程所
90
The most convenient and plentiful life which human being never had before is equipped with by the improvement of the science and technology. Unformatually, the pollution problem follows the progress of the science also and our environmental is destroyed gradually. The scientists around the world are doing their best to bring higher quality air back to the earth for us to breath. The main topic in this research is studying the influence of surface electric field intensity from the processing parameters for we to made the electret air filter and the efficiency of the filter after treated with the discharge process. The parameters in this research are voltage for discharge, the height of the electrodes, processing time in the electric field, temperature for pre-heating treatment, heating temperature in the electric field, cooling temperature and the type of the electrodes we use. In order to increase the stability of the surface electric field intensity of the electric filter, the equipment for elimination of the electrostatic is installed at the feeding area of the charging machine. Another way we use at the same time to increase the intensity of the surface electric field is to install a 165 W UV lamp at the position after the part of elimination of electrostatic in the machine. We wish the outer layer of the electron in the materials can be stimulated to get the stronger intensity of the surface electric field bring by the effect of opto-electret. By the result of this research, the better electric field intensity can be inquired by the fine needle type of the electrode and the charge intensity can be reached to 857.14 kV/m. The electret material can capture more charge if the pre-heating temperature can set as 60~65 0C and the intensity of the electric field is stronger also. The decrease about the intensity of the electric field intesity will become slower if the cooling temperature of the electret became 10 0C.
Chen, Bo-Syuan y 陳柏軒. "Broadband Electrical Field Intensity Detector". Thesis, 2012. http://ndltd.ncl.edu.tw/handle/42233612764521705289.
Texto completo國立勤益科技大學
電子工程系
100
This thesis proposed a broad band electrical field intensity detector. The circuit combines with logic integrated circuit and RF circuit. It can detect frequency from 50MHz to 3GHz. The detector can be used in RFID system, cellular phone and microwave oven signal detection. The detector also equipped with LED display and sound buzzer for different kinds of output in showing the strength of electric field. In comparison with the available products nowadays, this detector provides more cheaper, more smaller and effective operation benefit.
Wan, Xi-Haw y 萬子豪. "A Novel Dual-Electrode Plug to Achieve Intensive Electric Field for High Performance Ignition". Thesis, 2015. http://ndltd.ncl.edu.tw/handle/12475199352328026604.
Texto completo國立高雄第一科技大學
綠色能源及IC設計產業碩士專班
103
This thesis proposes a novel dual-electrode plug to achieve high performance ignition. The proposed plug not only can establish a much intensive electric field to promote ignition efficiency, but further saves fuel consumption and decreases exhaust emission. Furthermore, the proposed plug associated with a capacitor discharge ignitor (CDI) is able to ignite an engine system effectively, overcoming the disadvantage of long charging time caused from a traditional inductive discharging ignition (IDI). Thus, it has the particular feature of saving energy and is an eco-friendly product. To verify the proposed research, simulated waveforms and experimental results will be illustrated and explained in this thesis.
Mirza, Salma. "Scalable, Memory-Intensive Scientific Computing on Field Programmable Gate Arrays". 2010. https://scholarworks.umass.edu/theses/404.
Texto completoΤζινευράκης, Αντώνιος. "Συμβολή στην ανάλυση του ηλεκτρικού και του μαγνητικού πεδίου στο περιβάλλον εναερίων γραμμών ηλεκτρικής ενέργειας". Thesis, 2009. http://nemertes.lis.upatras.gr/jspui/handle/10889/2467.
Texto completoThis thesis is a contribution to the analysis of the electric field in the vicinity of single-circuit and double-circuit overhead power lines. Analytical formulas are developed for the accurate calculation of the intensity of the electric field as well as simpler approximate formulas. The proposed calculation method has arisen from the combination of the analysis of the conductors’ charges in their symmetrical components, the description of the intensity of the electric field using double complex numbers and the use of multipole expansions to express the intensity of the electric field. The use of double complex numbers allows the simultaneous representation of sinusoidal varying quantities (voltages and charges) and geometrical distances with complex numbers. The multipole expansion is a series of infinite terms, where each term is inversely proportional to an increasing power of the distance. Accurate analytical formulas are also developed as well as simpler approximate formulas for the calculation of the magnetic flux density produced by double-circuit lines. For the development of those formulas the use of double complex numbers is combined with the multipole expansion to express the magnetic flux density.