Journal articles: 'Flat high frequency coil'

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Weigelt, Michael, Cornelius Thoma, Erdong Zheng, and Joerg Franke. "Finite-element-analysis of the mechanical behavior of high-frequency litz wire in flat coil winding." Production Engineering 14, no. 5-6 (November 17, 2020): 555–67. http://dx.doi.org/10.1007/s11740-020-00996-3.

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AbstractNumerous applications of daily life use flat coils, e.g. in the automotive area, in solar technology and in modern kitchens. One common property that all these applications share, is a flat coil made of high-frequency (HF) litz wires. The coil layout and the properties of the HF litz wire influence the winding process and the efficiency of the application. As a result, the HF litz wire must meet the complex technical requirements of the winding process and of the preferred mechanical, electromagnetic and thermal properties of the HF litz wire itself. Therefore, a reasonable configuration and optimization of HF litz wire has been developed with the help of a finite-element-analysis (FEA). In this work, it is first shown that the mechanical behavior of HF litz wire under tensile and bending stress can be simulated. Since the computational effort for modelling an HF litz wire at the single conductor level is hardly manageable, a suitable modelling strategy is developed and applied using geometric analogous models (GAM). By using such a model, HF litz wires can be designed for the specific application and their behavior in a winding process can be predicted.

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Sağlam, Üstün, and Ahmet Tekin. "Resonance-filtering combo system for continuous wireless charging range coverage." Wireless Power Transfer 7, no. 2 (September 2020): 116–25. http://dx.doi.org/10.1017/wpt.2020.12.

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AbstractDistribution of wireless power charging field uniformly on a large area pad is critical for power receivers, particularly for wearable devices, wherein small form factor coils are involved. Since the receiver coil size is quite limited in these types of applications, the device is very sensitive to the amount of field it could retain and hence, it needs special placement or snapping mechanism to fix it at an optimum location for reliable wireless charging. In order to overcome this limitation for the end-user, a dual-mode multi-coil power transceiver system is proposed; utilizing resonance filtering to increase the amount of total power delivered with the rather uniform spatial distribution. Two concentric coils; center one driven by 6.78-MHz high-frequency driver (A4WP) and the outer larger one with a 200-KHz low-frequency driver (Qi) with resonant blocker could transfer up to 50 mW standards compliant flat power to a 13-mm radius 30-turns wearable receiver coil everywhere across an 8-cm radius charging pad area without any alignment requirement or snapping. Two different feedback topologies corresponding to each of the H-Bridge power drivers were also presented as an automatic series resonance coil drive frequency lock mechanism, extracting peak powers for each system individually from a standard 5 V-1A USB wall charger.

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Batygin, Yuriy, Olena Yeryomina, Svitlana Shinderuk, Evgeniy Chaplygin, and Badr Eddin Bensbaa. "FLAT CIRCULAR SOLENOID BETWEEN MASSIVE BIFILAR COILS. ANALYSIS OF ELECTROMAGNETIC PROCESSES." Bulletin of the National Technical University «KhPI» Series: New solutions in modern technologies, no. 1(7) (April 23, 2021): 3–8. http://dx.doi.org/10.20998/2413-4295.2021.01.01.

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An analysis and numerical estimates of induction effects in the metal of a flat circular solenoid located between the branches of an external bifilar coil in a flat inductor system excited by unidirectional currents in the bifilar windings are presented. Such a device, the design of which was first proposed earlier by the authors of this work, is of practical interest for circuits of equipment for magnetic-pulse processing of metals. The use of the considered inductor system makes it possible to minimize the influence of induction effects on electromagnetic processes in the metal of the internal inductor. Numerical estimates are obtained for the induced currents excited in the metal of the inner circular inductor placed between the outer windings of the bifilar coil. It is shown that in the low-frequency mode of acting fields, the time dependence of the excited current is a derivative of the time dependence of the exciting current and the transverse distribution of the current in the metal of the internal inductor is a linear dependence passing through the central axis of the inductor. In the high-frequency regime of acting fields, the time dependence and the radial distribution of the excited current coincide with the corresponding analogs for the exciting current, and the transverse distribution of the induced current is characteristic of a sharp surface effect, when the induced current is displaced to the boundary surfaces of the metal. It is proved that the minimum influence of the fields of the external bifilar on the electromagnetic processes in the internal inductor should be observed in the low-frequency mode, when the spatial superposition of multidirectional induced currents adds up to the zero value of the excited electromotive force of induction. The results of the analysis based on the specific calculations performed are aimed at finding the conditions for the successful technical implementation of the proposed inductor system. The creation of workable models of the proposed inductor systems and experiments to determine the real conditions for their maximum efficiency are seen as very promising in the direction of subsequent research.

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Sugandi, Gandi, and Majlis Burhanuddin Yeop. "Fabrication of MEMS Based Microspeaker Using Bulk Micromachining Technique." Advanced Materials Research 254 (May 2011): 171–74. http://dx.doi.org/10.4028/www.scientific.net/amr.254.171.

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The advantages of micromachining over conventional fabrication include precise dimensional control, integration of on-chip circuits and potential low cost owning to batch processing. Fabrication microspeaker for hearing instrument application using MEMS technology is challenging because of certain critical requirements, including their small size, low driving voltage, high output sound pressure level, flat frequency response and low energy consumption. A small in size, lightweight, and low cost microspeaker is demanded for application such as cellular phones and hearing aids. The device consist of two part; first parts is a micromachined polyimide membrane as the sound generating plate, where thevoice coil placed on the top of membrane, and the coil is a single loop voice coil. The second part is back plate permanent magnet. The disc permanent magnet bonded on acoustic hole plate is Neodymium-Iron-Boron (NdFeB) with magnetization of 1.45 T, diameter 1.6 mm, and thickness 0.8 mm. The fabrication process and performance of the first result device is discussed, and the thickness of electroplated single loop voice coil copper 10 mm and acoustic hole bonded together. The total size of the microspeaker chip is 5 mm x 5 mm x 1.5 mm, polyimide membrane thickness 2 mm.

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Wilken, Dennis, Daniel Zwick, Bente Sven Majchczack, Ruth Blankenfeldt, Ercan Erkul, Simon Fischer, and Dirk Bienen-Scholt. "Multi-Coil FD-EMI in Tidal Flat Areas: Prospection and Ground Truthing at a 17th Century Wooden Ship Wreckage." Remote Sensing 14, no. 3 (January 20, 2022): 489. http://dx.doi.org/10.3390/rs14030489.

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We present a case study of multi-coil frequency-domain electromagnetic (FD-EMI) prospection of a wooden ship wreckage from the 17th century. The wreckage is buried in a sandbar in the German part of the tidal flat area of the North Sea. Furthermore, the wreckage was excavated in advance and covered again after investigation. This ground truthing background and the position of the wreckage makes it a unique investigation object to test the feasibility of FD-EMI for prospecting wooden archaeological objects in the high conductive sediments of tidal flat areas. Our results reveal the shape and position of the wreckage in terms of conductivity maps. The resulting signal change caused by the wreckage in conductivity is only 10% of the value of the water-saturated sandy background, respectively, making a cautious process necessary, including a precise height correction. The data, furthermore, reveals a sensitivity to the vertical shape of the wreckage and thus sufficient depth sensitivity, but with reduced sensing depth. The study highlights the great potential of EMI for both in situ heritage management and archaeological research in the Wadden Sea.

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Zhou, Jie, De-jun Li, and Ying Chen. "Efficiency Improvement of Underwater Midrange Inductive Contactless Power Transmission Via a Relay Resonator." Marine Technology Society Journal 48, no. 3 (May 1, 2014): 73–87. http://dx.doi.org/10.4031/mtsj.48.3.3.

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AbstractInductive contactless power transmission (ICPT) offers a safe and convenient means of delivering energy underwater. However, ICPT is capable of transferring power effectively only within a near-distance range (millimeters). In recent years, magnetic resonance coupled power transmission (MRCPT), which can wirelessly deliver power across a distance of meters, has been introduced and studied. Nevertheless, MRCPT is usually operated at a very high resonance frequency (MHz) and is unavailable for underwater applications because of the considerable power loss in water. In this paper, we present an ICPT system with a relay resonator for a midrange efficiency improvement. The proposed system is based on an (inductor-capacitor) LC resonance circuit, rather than magnetic resonance. The system operates at a lower resonance frequency than the typical MRCPT system. A theoretical model is introduced for the proposed system using coupled mode theory. Theoretical treatments and an analysis of the system parameters are presented for improving the efficiency in underwater environments. The inductance and stray capacitance of a relay coil with a flat spiral profile are calculated. The experimental results indicate that the proposed system can substantially enhance the power transmission efficiency under water in midrange distances (≥10 cm) compared with the ICPT system without a relay resonator.

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Santos, Edson Costa, Katsuyuki Kida, Justyna Rozwadowska, Takashi Honda, Koshiro Mizobe, and Takuya Shibukawa. "Microstructure and Rolling Contact Fatigue Strength of Induction Heated AISI 52100 Bearings." Advanced Materials Research 566 (September 2012): 288–92. http://dx.doi.org/10.4028/www.scientific.net/amr.566.288.

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In the present work the microstructure and the rolling contact fatigue properties of induction heated AISI 52100 bearings are investigated. The bearings were heat treated by using a flat coil at 30 kW power and 60 kHz frequency, cooled with water and subsequently tempered for 1 hour at 180 °C. The hardness at the surface of the material was close to 900 HV0.3kgf/15s. The hardening depth of the induction heated sample was higher than 5 mm. The retained austenite content was around 18% at the surface and decreases along with the depth. The samples were rolling contact fatigue (RCF) tested up to 107 and 4.5x107 cycles, at Hertzian stress 4 GPa. No flaking failure was observed on the bearing races. For tests up to 107 cycles the track size was around 690 um and this remained unchanged up to 4.5x107 cycles. The residual stresses at the material surface before testing were close to zero and became highly compressive after the RCF testing. Stress induced transformation occurred at the surface and the retained austenite content after testing reached around 10%. Induction heating was successfully applied to induce martensitic transformation in AISI 52100 steel and the bearings showed very high fatigue strength under rolling contact.

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Wilt, M. J., D. L. Alumbaugh, H. F. Morrison, A. Becker, K. H. Lee, and M. Deszcz‐Pan. "Crosswell electromagnetic tomography: System design considerations and field results." GEOPHYSICS 60, no. 3 (May 1995): 871–85. http://dx.doi.org/10.1190/1.1443823.

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Electrical conductivity is an important petroleum reservoir parameter because of its sensitivity to porosity, pore fluid type, and saturation. Although induction logs are widely used to obtain the conductivity near boreholes, the poor resolution offered by surface‐based electrical and electromagnetic (EM) field systems has thus far limited obtaining this information in the region between boreholes. Low‐frequency crosswell EM offers the promise of providing subsurface conductivity information at a much higher resolution than was previously possible. Researchers at Lawrence Livermore National Lab (LLNL) and Lawrence Berkeley Laboratories (LBL), together with an industrial consortium, recently began a program to conduct low‐frequency crosswell EM surveys and develop suitable inversion techniques for interpreting the data. In developing the field instrumentation we used off‐the‐shelf components whenever possible, but custom‐designed induction coil transmitters and receivers were built for the field experiments. The assembled field system has adequate power for moderate to high‐resolution imaging, using boreholes spaced up to 500 m apart. The initial field experiment was undertaken in flat lying terrain at the British Petroleum test site in Devine, Texas. Using wells spaced 100 m apart, we collected a complete crosswell EM data set encompassing a 30 m thick, 10 ohm‐m limestone layer at a depth of 600 m. The resulting profiles were repeatable to within 1% and showed an excellent sensitivity to the layered structure, closely matching the borehole induction resisitivity log. At the UC Richmond field station, crosswell EM measurements were made to track an injected slug of salt water. Conductivity images of data collected before and after injection showed a clear anomaly as a result of the salt water plume and indicated that the plume had migrated in a northerly direction from the injection borehole.

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Batygin, Yu, T. Gavrilova, Ev Chaplygin, S. Shinderuk, and Yu Shcherbinina. "ELECTROMAGNETIC PROCESSES IN A SYSTEM WITH A PLANE CIRCULAR SOLENOID BETWEEN MASSIVE BIFILARY COILS." Electromechanical and energy saving systems 3, no. 55 (2021): 8–14. http://dx.doi.org/10.30929/2072-2052.2021.3.55.8-14.

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Purpose. Currently, in order to save materials and energy costs, devices have been developed using inductor systems with bifilar coils used in equipment for magnetic-pulse processing of metals. The purpose of this work is to obtain design relations based on a rigorous solution of the edge electrodynamics for the analysis of electromagnetic processes in a real metal of a circular solenoid of finite thickness placed between massive multi-turn coils of a bifilar with unidirectional currents in a flat inductor system. Methodology. To solve this problem, Maxwell’s equations with appropriate boundary conditions and Laplace transforms were used. Results. Based on the exact solution of the boundary value problem, the space-time function of the density of the induced current, which arises in a flat solenoid when the system is excited by harmonic unidirectional currents in massive bifilar windings, is obtained. On the basis of numerical calculations, it was found that in the low-frequency mode, the transverse distribution of the induced current is linear, symmetric about the central axis of the inductor. In the high-frequency mode, the transverse distribution of the induced current is characteristic of the case of a sharp surface effect. The conditions for the minimum influence of the fields of the external bifilar on the processes in the internal inductor are revealed. Originality. The novelty of this work lies in proposing the idea of the design of the inductor system, as well as in the exact solution of the electrodynamics problem and obtaining the calculated expressions for the analysis of electromagnetic processes. Practical value. On the basis of the obtained formulas and the performed calculations, the efficiency of the proposed calculation model has been proved, which makes it possible to use it as a basic model for similar inductor systems in determining the real conditions of their maximum efficiency. Figures 2, references 17.

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Pfaffhuber, Andreas A., Stefan Hendricks, and Yme A. Kvistedal. "Progressing from 1D to 2D and 3D near-surface airborne electromagnetic mapping with a multisensor, airborne sea-ice explorer." GEOPHYSICS 77, no. 4 (July 1, 2012): WB109—WB117. http://dx.doi.org/10.1190/geo2011-0375.1.

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The polar ocean’s sea ice cover is an unconventional and challenging geophysical target. Helicopter electromagnetic (HEM) sea-ice thickness mapping is currently limited to 1D interpretation due to traditional procedures and systems. These systems are mainly sensitive to layered structures, ideally set for the widespread flat (level) ice type. Because deformed sea ice (e.g., pressure ridges) is 3D and usually also heterogeneous, ice thickness errors up to 50% can be observed for pressure ridges using 1D approximations for the interpretation of HEM data. We researched a new generation multisensor, airborne sea ice explorer (MAiSIE) to overcome these limitations. Three-dimensional finite-element modeling enabled us to determine that more than one frequency is needed, ideally in the range 1–8 kHz, to improve thickness estimates of grounded sea-ice pressure ridges that are typical of 3D sea ice structures. With the MAiSIE system, we found a new electromagnetic concept based on one multifrequency transmitter loop and a 3C receiver coil triplet with active digital bucking. The relatively small weight of the EM components freed enough payload to include additional scientific sensors, including a cross-track lidar scanner and high-accuracy inertial-navigation system combined with dual-antenna differential GPS. Integrating the 3D ice-surface topography obtained from the lidar with the EM data at frequencies from 500 Hz to 8 kHz in [Formula: see text]-, [Formula: see text]-, and [Formula: see text]-directions, significantly increased the accuracy of sea-ice pressure-ridge geometry derived from HEM data. Initial test flight results over open water showed the proof-of-concept with acceptable sensor drift and receiver sensitivity. Noise levels were relatively high (20–250 parts-per-million) due to unwanted interference, leaving room for optimization. The 20 ppm noise level at 4.1 kHz is sufficient to map level ice thickness with 10 cm precision for sensor altitudes below 13 m.

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Islahudin, Islahudin, and M. Firman Ramdhan. "VIBRATION SENSOR BASED ON FLAT KOIL FOR EARTHQUAKE EARLY DETECTION IN LOMBOK NUSA TENGGARA BARAT REGION." Prisma Sains : Jurnal Pengkajian Ilmu dan Pembelajaran Matematika dan IPA IKIP Mataram 1, no. 2 (December 21, 2013): 161. http://dx.doi.org/10.33394/j-ps.v1i2.1015.

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In this research has been developed the application of flat coil as vibration sensor for early detection of earthquake. The flat coil is a very thin wire winding and acts as an inductor. This flat coil along with the capacitor constructs an oscillator which generates frequencies depending on the value of inductance and capacitance. This oscillator is called the LC oscillator. The flat coil inductance depends on the distance of the metal object in front of the flat coil. If the inductance changes, the frequency will change as well. Frequency can be converted into voltage form to represent distance. This effect is then applied to low frequencies using a pendulum on the sensor housing. The sensor system created can measure low-frequency vibrations in the range 0.26 - 1.0 Hz. Based on the research, the vibration sensor that has been made can measure one of the low frequency vibrations of 0.468 Hz at the frequency of 0.46 Hz vibration source

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Levshin, G. E. "Magnetization of ferromagnetic charge at induction heating." Izvestiya. Ferrous Metallurgy 65, no. 2 (March 16, 2022): 85–91. http://dx.doi.org/10.17073/0368-0797-2022-2-85-91.

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The article presents analysis of magnetization and heating of ferromagnetic charge in crucibles of induction furnaces of two types. In inductor furnaces, the charge is magnetized by a vertical electromagnetic flow, and in electromagnetic furnaces with a curved U-, C-, or O-shaped magnetic circuit (MPr) – by a horizontal flow. Knowledge of these largely general magnetization processes is insufficient. Bi magnetic induction in charge material is rather important. There are difficulties in determining this parameter during magnetization of a single piece of charge and other magnetic quantities associated with it: Bm induction and Nm strength of the demagnetizing field, N demagnetization coefficient, M magnetization, magnetic permeabilities of μi substance and μt body, km susceptibility, etc. Difficulties increase at magnetization, if it is a porous body with crucible volume of ~V t and a factor of filling with ferromagnetic pieces of this volume of Kv ≤ 0.5. It also creates a demagnetizing field with Bmt induction and Hmt strength. Beyond that, pores have an additional demagnetizing effect. Therefore, the induction Вiт in a porous body is less than the induction Вi in a solid one. To compare magnetization of ferromagnetic charge with horizontal and vertical flows with frequency of 50 Hz, modeling experiments were carried out with the samples of DSL08 unconsolidated shot from high-carbon steel (GOST 11964 – 83) with Kv ≈ 0.53. The samples were placed in the inductor and between the poles of a U-shaped core piece. Induction was measured by a cylindrical and flat probe unit of Sh1-15 militeslameter in air and in the sample. An advantage of electromagnetic furnace over an inductor one is more uniform distribution of Bi induction in charge and its significant excess (1.7 times) over the Be induction in a furnace working cavity, which indicates more efficient use of electromagnetic energy in this furnace during heating. The author proposed to control Вi induction when heating the charge by the ammeter-voltmeter method using measuring coil made of heat-resistant wire.

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Bailo, Kelly C., Diann E. Brei, and Karl Grosh. "Investigation of Curved Polymeric Piezoelectric Active Diaphragms." Journal of Vibration and Acoustics 125, no. 2 (April 1, 2003): 145–54. http://dx.doi.org/10.1115/1.1547461.

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Piezoelectric active diaphragms hold promise as an alternative to using passive diaphragms driven by voice coils for sound generation and noise cancellation applications. This paper presents an in-depth investigation of the acoustic response for curved polymeric piezoelectric active diaphragms. Simple analytical models were derived and experimentally validated to predict the structural dynamic and acoustic responses for generic polyvinylidene fluoride (PVdF) constant curvature active diaphragms with variable geometric parameters (width, radius, subtended angle, thickness). These models are useful for design purposes and for capturing the overall behavioral trends. To analyze the acoustic response mechanisms further, three-dimensional numerical models were also developed and experimentally validated. Parametric studies based upon these models reveal the potential of high acoustic outputs (over 100 dB in the far field) from optimized geometric configurations with subtended angles differing from the conventionally utilized flat, semicircular or circular configurations. These studies, corroborated by experiments on a variety of active diaphragm prototypes, conclude that the acoustic output is governed by the structural ring resonance, which can be designed such that the most efficient acoustic radiation is within the particular frequency range of operation.

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Kumalasari, Ratih, Mitra Djamal, and Edi Sanjaya. "Design and Development of Instrument for Measuring Torque and Shear Modulus for Material Research." Advanced Materials Research 875-877 (February 2014): 2123–27. http://dx.doi.org/10.4028/www.scientific.net/amr.875-877.2123.

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An Instrument for measuring torque and shear modulus based on flat coil element for material research has been developed. Flat coil element was made from a thin epoxy with number of coils 30 and outer diameter of 3 cm. Working principle of the sensor is based on position change of a disturb element which attached to test shaft in front of the flat coil. The change of position will change the total inductance of the sensor system. The change of inductance is measured using LC oscillator by measuring its resonant frequency. An F/V converter converts the resonance frequency into voltage. The flat coil is used to measure the change of angle of the developed torque instrument. Using microcontroller ATMEGA16 the developed instrument can be controlled and work automatically. The developed instrument can measure torque and shear modulus with relative error less than 3%

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Aliteh, Nor, Norhisam Misron, Ishak Aris, Roslina Mohd Sidek, Kunihisa Tashiro, and Hiroyuki Wakiwaka. "Triple Flat-Type Inductive-Based Oil Palm Fruit Maturity Sensor." Sensors 18, no. 8 (August 1, 2018): 2496. http://dx.doi.org/10.3390/s18082496.

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This paper aims to study a triple flat-type air coil inductive sensor that can identify two maturity stages of oil palm fruits, ripe and unripe, based on the resonance frequency and fruitlet capacitance changes. There are two types of triple structure that have been tested, namely Triple I and II. Triple I is a triple series coil with a fixed number of turns (n = 200) with different length, and Triple II is a coil with fixed length (l = 5 mm) and a different number of turns. The peak comparison between Triple I and II is using the coefficient of variation cv, which is defined as the ratio of the standard deviation to the mean to express the precision and repeatability of data. As the fruit ripens, the resonance frequency peaks from an inductance–frequency curve and shifts closer to the peak curve of the air, and the fruitlet capacitance decreases. The coefficient of the variation of the inductive oil palm fruit sensor shows that Triple I is smaller and more consistent in comparison with Triple II, for both resonance frequency and fruitlet capacitance. The development of this sensor proves the capability of an inductive element such as a coil, to be used as a sensor so as to determine the ripeness of the oil palm fresh fruit bunch sample.

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Kim, Hyung Sik, Sang Pyo Hong, Mi Hyun Choi, Hyun Joo Kim, In Hwa Lee, Na Rae You, Jeong Han Yi, and Soon Cheol Chung. "A Study on the Characteristics of a Vibrator Using Flat PCB-Coil." Applied Mechanics and Materials 392 (September 2013): 738–42. http://dx.doi.org/10.4028/www.scientific.net/amm.392.738.

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In this study, we developed and evaluateda vibrator using a flat PCB-coil. The flat PCB-coil vibrator was fabricated on a printed circuit board using and etching process. The spiral pattern was etched on a fiberglass cloth with an epoxy resin. To evaluatethe flat PCB-coil vibrator, we generated a sine wave, saw-tooth, and square wave through a custom made wave generator and amplified the waveforms using a power amplifier. A three-axis accelerometer was used to evaluate the performance of the developed vibrator. Even though the developed vibrator is simple, it has a wide range of vibration frequency (50~500 Hz) and vibration amplitude (0~5 V). The vibration amplitude does not change due to frequency change. It is expected that the developed vibrator can be used in a wide variety of applications such as in a tactile stimulator, in elastography, energy harvesting, and in a cooling system.

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Vaughan, J. T., G. Adriany, C. J. Snyder, J. Tian, T. Thiel, L. Bolinger, H. Liu, L. DelaBarre, and K. Ugurbil. "Efficient high-frequency body coil for high-field MRI." Magnetic Resonance in Medicine 52, no. 4 (2004): 851–59. http://dx.doi.org/10.1002/mrm.20177.

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Yabukami, S., M. Watanabe, H. Kikuchi, M. Yamaguchi, and K. I. Arai. "High-Frequency Permeance Measurements Using a Microstrip Coil." Journal of the Magnetics Society of Japan 20, no. 2 (1996): 589–93. http://dx.doi.org/10.3379/jmsjmag.20.589.

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Yoda, Kiyoshi, Tadatoshi Yamada, and Satoshi Fujimura. "4728894 High frequency coil for an NMR apparatus." Magnetic Resonance Imaging 6, no. 6 (November 1988): IV—V. http://dx.doi.org/10.1016/0730-725x(88)90118-x.

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Yamamoto, Etsuji, Takashi Onodera, and Hideki Kohno. "4748412 High-frequency coil for nuclear magnetic resonator." Magnetic Resonance Imaging 7, no. 4 (July 1989): VI. http://dx.doi.org/10.1016/0730-725x(89)90513-4.

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Liu, Jun, Gang Yi Zhou, Xin Long Dong, and Guo Fu Li. "System Design for High Energy Rate Electromagnetic Powder Compaction Devices." Advanced Materials Research 97-101 (March 2010): 1146–49. http://dx.doi.org/10.4028/www.scientific.net/amr.97-101.1146.

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In this paper, the main element is constructed high energy electromagnetic compaction system on the high-energy flat coil. Physical model for analyzing dynamic response of high pulse current was reviewed. Design loading device using high energy electromagnetic technology to suppress powder, consider the exhaust, stripping, loading, positioning and other issues,propose a more reasonable program.The device includes various components of the installation. such as coil, the coil plate, driver, amplifiers, punching first, die, upper and lower fixing plate. The model of device based on Pro/E to facilitate manufacturing.Pressure embryo along the suppression direction has more uniform density distribution.The technology possesses advantagesof the single side forming and directional loading.

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Ishibashi, Masaki, Keigo Okagawa, and Tomokatsu Aizawa. "Electromagnetic Bulging of Stainless Steel Sheet by Using Flat One-Turn Coil." Materials Science Forum 673 (January 2011): 101–6. http://dx.doi.org/10.4028/www.scientific.net/msf.673.101.

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In this paper, we describe an electromagnetic bulging for a SUS304-O stainless steel sheet (0.15 mm thick) and its experimental results. In the die forming, the flat one-turn coil is adopted for the bulging of the SUS304-O sheet, when an aluminum sheet (0.3 mm thick) as a driving plate (driver) is used together. When an impulse current from an energy-storing capacitor bank passes through the flat one-turn coil, a high-density magnetic flux is suddenly generated around the coil. Eddy currents are induced in the driver placed on the coil. The SUS304-O sheet is pressed by an electromagnetic force generated in the driver, leading to bulge into a meandering groove with small concave shape. The bank energy required for the bulging of 12mm wide, 60mm long and 0.43mm high is about 4.5 kJ, and the obtained workpiece does not almost have wrinkles and curves.

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Rainey, Jan K., Jeffrey S. DeVries, and Brian D. Sykes. "Estimation and measurement of flat or solenoidal coil inductance for radiofrequency NMR coil design." Journal of Magnetic Resonance 187, no. 1 (July 2007): 27–37. http://dx.doi.org/10.1016/j.jmr.2007.03.016.

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Yabukami, S., M. Yamaguchi, and K. I. Arai. "High Frequency Permeance Measurements Using a Shielded Loop Coil." Journal of the Magnetics Society of Japan 21, no. 4_2 (1997): 813–16. http://dx.doi.org/10.3379/jmsjmag.21.813.

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Shin, Sung-Yong, Kwang-Ho Shin, Jong-sung Kim, Young-Hak Kim, Sang-Ho Lim, and Geon Sa-gong. "High frequency permeameter with semi-rigid pick-up coil." Journal of Magnetism and Magnetic Materials 304, no. 1 (September 2006): e480-e482. http://dx.doi.org/10.1016/j.jmmm.2006.02.256.

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Yamaguchi, M., S. Yabukami, and K. I. Arai. "High frequency magnetic field sensing coil using microstrip line." IEEE Transactions on Magnetics 31, no. 6 (1995): 3173–75. http://dx.doi.org/10.1109/20.490318.

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Piskunkov, A. F., and I. V. Kravchenko. "The Plasma Ionization Mechanism for a Radio Frequency Ion Thruster with a Flat Coil Inductor." Thermal Engineering 65, no. 13 (December 2018): 1029–35. http://dx.doi.org/10.1134/s0040601518130153.

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Lee, Woochan, and Dukju Ahn. "Wireless Power Transfer under Wide Distance Variation Using Dual Impedance Frequency." Electronics 9, no. 1 (January 7, 2020): 110. http://dx.doi.org/10.3390/electronics9010110.

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A dual-impedance operation, where coil impedance is controlled by operating frequency selection, is proposed to maintain optimum reflected impedance across coupling variation. More specifically, this work focuses on how high coupling between coils presents excessively high reflected resistance to transmitter (Tx) inverters, degrading the efficiency and output power of the inverter. To overcome this problem, the proposed system is equipped with dual-impedance coil and selects high- or low-impedance coil based on the ability to operate both at 200 kHz and 6.78 MHz frequencies. The reactive impedances of 6.78 MHz coils are designed to be higher than that of 200 kHz coils. Since the reflected resistance is proportional to the coil impedances and coupling squared, at close distance with high coupling coefficient, 200 kHz coils with low coil impedances are activated to prevent an excessive rise in reflected resistance. On the other hand, at large distance spacing with low coupling coefficient, 6.78 MHz coils with high coil impedances are activated so that sufficient reflected resistance is obtained even under the small coupling. The proposed system’s advantages are the high efficiency and the elimination of bulky mechanical relay switches. Measured efficiencies are 88.6–50% across 10 coupling variations.

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Kim, Kyungmin, and Eakhwan Song. "High-Frequency Modeling of Printed Spiral Coil Probes for Radio-Frequency Interference Measurement." Journal of Korean Institute of Electromagnetic Engineering and Science 29, no. 1 (January 2018): 10–19. http://dx.doi.org/10.5515/kjkiees.2018.29.1.10.

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30

Yang, Cheng Ju, Cheng Wei Zhang, Geng Bin Zhang, Pei Ling Chen, and Shi Jun Xie. "Research on High Bandwidth Rogowski Coil for Measuring Lightning Traveling Wave Current on Double Circuit Transmission Line." Advanced Materials Research 986-987 (July 2014): 1558–64. http://dx.doi.org/10.4028/www.scientific.net/amr.986-987.1558.

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Double circuit transmission line is an important part of the power grid, which is vulnerable to lightning and may endanger the security and stability of the power grid. In order to design a sensor which can monitor the lightning traveling wave current on double circuit transmission line, simulations of lightning on the double circuit transmission line were conducted. The simulation result shows that besides high frequency components, the traveling wave contains a lot of low frequency components. Based on the equivalent model and the frequency response of the self-integrated Rogowski coil, it turns out that the widely used self-integrated Rogowski coil is not suitable for this application as the problem of low frequency distortion. In this paper, through theoretical analysis and simulations in Matlab, an improved Rogowski coil with analog integrator is proposed which can correct the low frequency distortion of the self-integrated Rogowski coil. All the simulations, experiments and operating data installed to a double circuit transmission line in China verify the validity of the high bandwidth Rogowski coil.

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31

Gor’kov, Peter L., Eduard Y. Chekmenev, Riqiang Fu, Jun Hu, Timothy A. Cross, Myriam Cotten, and William W. Brey. "A large volume flat coil probe for oriented membrane proteins." Journal of Magnetic Resonance 181, no. 1 (July 2006): 9–20. http://dx.doi.org/10.1016/j.jmr.2006.03.008.

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32

YAMASHITA, Mutsuo, and Jhoji KAGAMI. "Trial Production of Coil-Target-Type High-Frequency Sputter Apparatus." SHINKU 39, no. 2 (1996): 57–64. http://dx.doi.org/10.3131/jvsj.39.57.

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Wei Bing, 卫兵, 卿燕玲 Qing Yanling, 关永超 Guan Yongchao, 仇旭 Qiu Xu, 付佳斌 Fu Jiabin, and 宋盛义 Song Shengyi. "Self-integrated Rogowski coil for low-frequency high current measurement." High Power Laser and Particle Beams 22, no. 9 (2010): 2227–22231. http://dx.doi.org/10.3788/hplpb20102209.2227.

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34

Enokizono, M., T. Todaka, H. Nakamura, and R. Fukuda. "Improvement of the Coil Construction in High-Frequency Induction Heating." Journal of the Magnetics Society of Japan 22, no. 4_2 (1998): 877–80. http://dx.doi.org/10.3379/jmsjmag.22.877.

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35

Ocilka, Matus, Dobroslav Kovac, Irena Kovacova, Jan Perdulak, Andrii Gladyr, Dmytro Mamchur, Iurii Zachepa, Tibor Vince, and Jan Molnar. "Serial Resonant Converter and Load Coil for High Frequency Heating." Communications - Scientific letters of the University of Zilina 15, no. 3 (August 31, 2013): 56–62. http://dx.doi.org/10.26552/com.c.2013.3.56-62.

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36

Zhang, Xian, Xuejing Ni, Bin Wei, Songcen Wang, and Qingxin Yang. "Characteristic Analysis of Electromagnetic Force in a High-Power Wireless Power Transfer System." Energies 11, no. 11 (November 8, 2018): 3088. http://dx.doi.org/10.3390/en11113088.

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In order to explore the influence of the electromagnetic force (EMF) on the coupling mechanism in a high-power wireless power transfer (WPT) system, the characteristics of the EMF are investigated by theoretical calculation and simulation. The expressions of the EMF on the WPT structure with magnetic shielding are derived in time domain and frequency domain, respectively. The EMF is divided into Lorentz force and Kelvin force. The distribution and changing regularity of the EMF on the coil and the magnetic shield under different exciting currents are solved by the finite element model, and the harmonic of the EMF is analyzed in detail. The results show that the coil is subjected to the EMF in both radial and axial directions. The EMF on the magnetic shield is opposite to the EMF on the coil, and the force between the transmitting coil and the receiving coil is repulsive. The frequency of the EMF is twice that of the system resonant frequency. An experimental prototype is built to prove the correctness of the predicted characteristics. It is shown that the EMF should be carefully considered in the application of high-power WPT systems.

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Mitha, Alim P., Benjamin Reichardt, Michael Grasruck, Eric Macklin, Soenke Bartling, Christianne Leidecker, Bernhard Schmidt, et al. "Dynamic imaging of a model of intracranial saccular aneurysms using ultra-high-resolution flat-panel volumetric computed tomography." Journal of Neurosurgery 111, no. 5 (November 2009): 947–57. http://dx.doi.org/10.3171/2009.2.jns08828.

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Object Imaging of intracranial aneurysms using conventional multidetector CT (MDCT) is limited because of nonvisualization of features such as perforating vessels, pulsatile blebs, and neck remnants after clip placement or coil embolization. In this study, a model of intracranial saccular aneurysms in rabbits was used to assess the ultra-high resolution and dynamic scanning capabilities of a prototype flat-panel volumetric CT (fpVCT) scanner in demonstrating these features. Methods Ten New Zealand white rabbits underwent imaging before and after clipping or coil embolization of surgically created aneurysms in the proximal right carotid artery. Imaging was performed using a prototype fpVCT scanner, a 64-slice MDCT scanner, and traditional catheter angiography. In addition to the slice data and 3D views, 4D dynamic views, a capability unique to fpVCT, were also created and reviewed. The images were subjectively compared on 1) 4 image quality metrics (spatial resolution, noise, motion artifacts, and aneurysm surface features); 2) 4 posttreatment features reflecting the metal artifact profile of the various imaging modalities (visualization of clip or coil placement, perianeurysmal clip/coil anatomy, neck remnant, and white-collar sign); and 3) 2 dynamic features (blood flow pattern and aneurysm pulsation). Results Flat-panel volumetric CT provided better image resolution than MDCT and was comparable to traditional catheter angiography. The surface features of aneurysms were demonstrated with much higher resolution, detail, and clarity by fpVCT compared with MDCT and angiography. Flat-panel volumetric CT was inferior to both MDCT and angiography in terms of image noise and motion artifacts. In fpVCT images, the metallic artifacts from clips and coils were significantly fewer than those in MDCT images. As a result, clinically important information about posttreatment aneurysm neck remnants could be derived from fpVCT images but not from MDCT images. Time-resolved dynamic sequences were judged slightly inferior to conventional angiography but superior to static MDCT images. Conclusions The spatial resolution, surface anatomy visualization, metal artifact profile, and 4D dynamic images from fpVCT are superior to those from MDCT. Flat-panel volumetric CT demonstrates aneurysm surface features to better advantage than angiography and is comparable to angiography in metal artifact profile. Even though the temporal resolution of fpVCT is not quite as good as that of angiography, fpVCT images yield clinically important anatomical information about aneurysm surface features and posttreatment neck remnants not attainable with either angiography or MDCT images.

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Sun, Haiyan, and Ling Sun. "An Improved Quad Flat Package for High Frequency SiP Applications." International Journal of Future Generation Communication and Networking 6, no. 6 (December 31, 2013): 37–46. http://dx.doi.org/10.14257/ijfgcn.2013.6.6.05.

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Nielsen, J. F., B. Klemar, and H. Kiilerich. "A New High-Frequency Magnetic Stimulator with an Oil-Cooled Coil." Journal of Clinical Neurophysiology 12, no. 5 (September 1995): 460–67. http://dx.doi.org/10.1097/00004691-199509010-00005.

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40

Kakuda, W., M. Abo, Y. Nakayama, A. Kiyama, and H. Yoshida. "High-frequency rTMS using a double cone coil for gait disturbance." Acta Neurologica Scandinavica 128, no. 2 (February 7, 2013): 100–106. http://dx.doi.org/10.1111/ane.12085.

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41

Yamashita, M. "Fundamental characteristics of built‐in high‐frequency coil‐type sputtering apparatus." Journal of Vacuum Science & Technology A: Vacuum, Surfaces, and Films 7, no. 2 (March 1989): 151–58. http://dx.doi.org/10.1116/1.575744.

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42

Yeo, K. S., H. P. Tan, J. G. Ma, and M. A. Do. "Three-dimensional integrated coil inductor on silicon for high-frequency applications." Microwave and Optical Technology Letters 31, no. 1 (2001): 23–24. http://dx.doi.org/10.1002/mop.1346.

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43

Roschmann, Peter. "4746866 High-frequency coil system for a magnetic resonance imaging apparatus." Magnetic Resonance Imaging 7, no. 4 (July 1989): V. http://dx.doi.org/10.1016/0730-725x(89)90509-2.

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44

Gevorgyan, S., T. Kiss, A. Movsisyan, H. Shirinyan, T. Ohyama, M. Takeo, T. Matsushita, and K. Funaki. "Advantages of measurement in flat geometry high- cuprates by an open-flat coil magnetometer demonstrating its wide possibilities for detection." Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment 444, no. 1-2 (April 2000): 471–75. http://dx.doi.org/10.1016/s0168-9002(99)01425-4.

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45

Li, Ping, Tao Liang, Yang Chun Cheng, and Liang Zhao. "Simulation Research on High-Frequency Response Characteristic of Rogowski Coil Based on the Distributed Parameter Model." Applied Mechanics and Materials 241-244 (December 2012): 758–62. http://dx.doi.org/10.4028/www.scientific.net/amm.241-244.758.

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According to the transfer impedance getting from distributed parameter model,we analyse the influences of the number of turns ,capacitance to the shield and interturn capacitance on the high frequency characteristic of Rogowski coil through theories and simulations. Simulation shows that there are a series of zeros in high frequency band, but on the whole, the high frequency response does not change with the increase of frequency. The number of turns and capacitance to the shield can influence the frequency at which zero appears, but the high frequency characteristic of Rogowski coil can’t be influenced. Considering the interturn capacitance, the curve of high-frequency response characteristic presents a "V" shape ", and this leads to the reduction of higher cut-off frequency. So we should try to decrease the interturn capacitance to reduce the influence on the high frequency characteristic.

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46

Niu, Wangqiang, Jiateng Jiang, Chen Ye, and Wei Gu. "Frequency splitting suppression in wireless power transfer using hemispherical spiral coils." AIP Advances 12, no. 5 (May 1, 2022): 055016. http://dx.doi.org/10.1063/5.0078744.

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In wireless power transfer (WPT) systems, frequency splitting phenomena always occur when the transfer distance is too small to obtain the maximum output efficiency in the working frequency. In this paper, a hemispherical spiral coil structure is proposed to suppress frequency splitting phenomena by containing the coupling the system without changing the original system size and transfer distance. Meanwhile, compared with the planar system, the hemispherical system can maintain high power and transfer efficiency and has better angular misalignment tolerance. A WPT system consisting of a hemispherical spiral coil and a planar spiral coil resonating at 110 kHz called the single hemispherical spiral coil WPT (SHWPT) system and another with two hemispherical spiral coils called the double hemispheric spiral coils WPT (DHWPT) system are suggested. Analytic models of these two structures are established to analyze the influence of the coil height on the frequency splitting. The critical coil height is closely related to the critical coupling that provides a reference for the design of the coil. Finally, the experimental results show that the hemispherical coil structure can suppress the frequency splitting to ensure the transmission stability of the WPT system. In the SHWPT system with a 1 cm inner diameter and a 13 cm outer diameter, the critical height of the coil is 5.2 cm, which can suppress frequency splitting when the transmission distance is 0 cm. In the DHWPT system, the critical height of the coil is 4.3 cm.

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Chen, Chien-Lung, and Chung-Wen Hung. "Improving LCC Series-Based Wireless Power Transfer System Output Power at High Temperature." Electronics 10, no. 22 (November 22, 2021): 2875. http://dx.doi.org/10.3390/electronics10222875.

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Adding a core to a coupling coil can improve transmission efficiency. However, the added core causes the self-inductance of the coupling coil to increase at a high temperature due to the temperature-sensitive property of the core material’s permeability. The self-inductance increases, causing the resonance frequency to shift down, thereby decreasing the output power. The 3 dB bandwidth of the system can learn of the correspondence between the output power and the resonance frequency. In order to make sure that the output power does not excessively decrease at a high temperature, this study employs a simulation for the LCC-S-based wireless power transfer system. Adding a minor resistance to shift down the lower cutoff frequency ensures that the resonance frequency yielded by the temperature rise can be higher than the lower cutoff frequency, making the output power higher than half of the maximum. Then, an adjustment on the compensation capacitances on the resonant circuit elevates the output power more. The outcomes are consistent with the prediction. Adding the core to the coupling coil improves transmission efficiency; increasing the bandwidth of the system excessively decreases the output power decline at a high temperature for the temperature-sensitive core material permeability.

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Ashraf, Khalid, Mohd Haris Md Khir, and John Ojur Dennis. "An Electromagnetic Frequency Increased Vibration Energy Harvester." Advanced Materials Research 403-408 (November 2011): 4231–34. http://dx.doi.org/10.4028/www.scientific.net/amr.403-408.4231.

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This paper presents an impact-based frequency increased electromagnetic vibration energy harvester to scavenge energy in a low frequency environment. To realize the novel impact based frequency up-conversion mechanism, a coil has been elastically anchored with a platform on which four permanent magnets are arranged in such a way that a strong closed magnetic flux path, linking the coil, is formed. The proposed scavenger has two dynamics of motion. The first phase is a low frequency oscillation to absorb energy from ambient vibration during which both the coil and magnet act as proof mass and move collectively. The increased proof mass ensures maximization of absorbed energy. After crossing a certain clearance, the platform containing magnetic setup rigidly and supporting the coil elastically, collides with a rigid stopper and bounces back. As a result of this mechanical impact a high frequency oscillation is setup in the coil relative to the magnets during which energy is transferred to electrical domain by electromagnetic induction. A macro-prototype has been build to prove the proposed concept. Initial test results show that the proposed harvester generates a peak voltage of 1 volt across a load of 220 Ω at an excitation frequency of 5 Hz which corresponds to a peak power of 4.5 mW and average power of 660 µW.

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Wang, H., L. Ciobanu, A. S. Edison, and A. G. Webb. "An eight-coil high-frequency probehead design for high-throughput nuclear magnetic resonance spectroscopy." Journal of Magnetic Resonance 170, no. 2 (October 2004): 206–12. http://dx.doi.org/10.1016/j.jmr.2004.07.001.

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Zhou, Bin, Huiling Wang, Hongtao Zhou, Ke Wang, and Shudong Wang. "Natural flat cocoon materials constructed by eri silkworm with high strength and excellent anti-ultraviolet performance." Journal of Engineered Fibers and Fabrics 15 (January 2020): 155892502097865. http://dx.doi.org/10.1177/1558925020978652.

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Eri silkworm is easy to be raised and has high cocoon yield, the cocoon fails to be continuously reeled due to a loose structure, a large part of cocoon coat and an eclosion hole. In this work, a fifth instar larvae of eri silkworm was provided with only a flat cocooning place to spin to produce a flat cocoon, it was fed with the castor leaves sprayed with nano-TiO2 and graphene oxide (GO), Compared with the flat cocoon obtained without nanomaterials, the silk was not found to change in morphology and structure significantly. Nanomaterials promoted the transformation of the random coil/α-helix conformation of the silk to the β-sheet conformation to a certain extent, which formed a stable crystallization. Thus its strength value could increase by 15%–17%, the ultraviolet protection factor ( UPF) value of the flat cocoon with nanomaterials increased significantly, and the silk obtained made up for the lack of the strength in natural eri silkworm silk and poor resistance to sunlight. The flat cocoon features a stable structure, good formation, uniform thickness, and manual control. It can be directly used as raw material for processing flat textile products, which provides a feasible idea for the high-value utilization of the eri silkworm cocoon.

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Journal articles on the topic 'Flat high frequency coil'

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