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142 articles for “low frequency”
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Research ArticleOpen accessPhrase in the titleModified Center Interpolation Net for Classification of Composite Structures Tested Using Low Frequency Electronic TappingMahmoud Z. IskandaraniProblem statement: Most exhaustive NDT techniques require large capital equipment, are difficult to apply to complex geometric structures and, above all, are time-consuming to use and some take a considerable time to complete. As a solution to the problems associated with NDT applications, there is a need to establish an intelligent analysis system that supports a portable testing environment, which … …American Journal of Applied Sciences, Vol. 7, Issue 2 · 28 Feb 2010 · 7,108 accessesView PDFCite
Research ArticleOpen accessPhrase in the titleEFFECT OF AMBIENT AIR CONDITIONS ON LOW FREQUENCY NEGATIVE CAPACITANCE OF NC-TIO2/P3HT HETEROJUNCTION SOLAR CELLSH. Al-DmourWe report the negative capacitance of nanocrystalline titanium dioxide/poly (3-hexyl thiophene), nc-TiO2/P3HT, heterojunction solar cells. In air, low frequency negative capacitance has been observed under forward bias associated with high values of conductance. Interestingly, the negative capacitance disappear when the device was placed in vacuum chamber. These results are attributed to affect the ambient conditions on the charge carrier concentration … …American Journal of Applied Sciences, Vol. 11, Issue 8 · 28 May 2014 · 6,482 accessesView PDFCite
Research ArticleOpen accessPhrase in the titleDesign of CHWHG Type Low Frequency Magnetic Fields GeneratorBo Cheng, Ahmed N. Abdalla, Xi Huang et al.Highly considering the invariability of magnetic field strength in the Magnetic Field Generators, which used to stimulate rat's nerve cell, surely improve the stimulation performance outcome. A new technique to get an invariable magnetic field strength within Magnetic Field Generator has been proposed, Furthermore it had implemented on microcontroller-based system providing an Alternating Magnetic Field Generator (AMFG) with a high … …Journal of Computer Science, Vol. 3, Issue 2 · 28 Feb 2007 · 6,965 accessesView PDFCite
Research ArticleOpen accessEvery word in the titleA LOW-COST EFFECTIVE UWB LOCATION SYSTEM BASED ON FREQUENCY SYNTHESIS TECHNOLOGYQilong Zhang, Fei QinWireless location system based on UWB signals has been widely utilized by wireless network recently, especially for the indoor scenarios where GPS signal has been heavily attenuated. However, due to the requirement of ultra wideband signals, existing location system usually faces problems including complexity, robust and cost, which limit the potential applications. In this study, we propose a new approach … …Journal of Computer Science, Vol. 10, Issue 12 · 26 Dec 2014 · 7,633 accessesView PDFCite
Research ArticleOpen accessEvery word in the titleModeling Method of a Low-Pass Filter Based on Microstrip T-Lines with Cut-Off Frequency 10 GHz by the Extraction of its Wave-Scattering Parameters from its Causal Bond Graph ModelHichem Taghouti, Abdelkader MamiProblem statement: This study presented a jointly application of bond graph technique and wave-scattering formalism for a new realization called scattering bond graph model which has the main advantage to show up explicitly the different wave propagation. Approach: For that, we proposed to find the scattering matrix from the causal bond graph model of a low-pass filter based on Microstrip … …American Journal of Engineering and Applied Sciences, Vol. 3, Issue 4 · 4 Nov 2010 · 8,262 accessesView PDFCite
Research ArticleOpen accessEvery word in the titleLow Power Phase Locked Loop Frequency Synthesizer for 2.4 GHz Band ZigbeeNesreen Mahmoud Hammam Ismail, Masuri OthmanProblem statement: Wireless communication systems are required for many applications. There are different standards for these systems. IEEE 802.15.4 defines the communication system standard for zigbee. This study discussed designing one of the blocks of zigbee transceiver which is the Phase Locked Loop (PLL). A major target for any communication systems is saving battery power, especially for zigbee as it … …American Journal of Engineering and Applied Sciences, Vol. 2, Issue 2 · 30 Jun 2009 · 8,057 accessesView PDFCite
Research ArticleOpen accessEvery word in the titlePeak to Average Power Ratio Reduction of Orthogonal Frequency Division Multiplexing System with a Significant Low ComplexityMahamod Ismail, J. S. Mandeep, Montadar Abas Taher, M. T. IslamThe Orthogonal Frequency Division Multiplexing (OFDM) has been widely used in many applications in the last decade. It provides good benefits compared to the single carrier systems. However, it has a bad property represented by the high-output Peak to Average Power Ratio (PAPR) which is considered as its major problem. There are many techniques to reduce the PAPR values such … …American Journal of Applied Sciences, Vol. 9, Issue 12 · 20 Dec 2012 · 6,589 accessesView PDFCite
Review ArticleOpen accessIn the keywordsArchitecture of Ultra Low Power Micro Energy Harvester Using RF Signal for Health Care Monitoring System: A ReviewFarah Fatin Zulkifli, Jahariah Sampe, Muhammad Shabiul Islam, Mohd Ambri MohamedThis research presents architecture of Ultra Low Power (ULP) Micro Energy Harvester (MEH) using Radio Frequency (RF) signal as an input. RF has many advantages compared to other ambient sources because it is not affected by changes of weather or time, does not require heat or wind exposure and it can be moved randomly within the bound of the transmission … …American Journal of Applied Sciences, Vol. 12, Issue 5 · 7 Jul 2015 · 6,956 accessesView PDFCite
Research ArticleOpen accessIn the keywordsPower System Oscillations Damping Using Unified Power Flow Controller-Based StabilizerLokman H. Hassan, M. Moghavvemi, Haider A.F. MohamedProblem statement: The Phillips-Heffron model of a power system with UPFC published by AJAS, demonstrates the effect of the UPFC in improving power system oscillation stability. Unfortunately, some of the equations have not been correctly derived and so working with this model in its existing form is misleading. Approach: In this study, the model is revisited and the equations are … …American Journal of Applied Sciences, Vol. 7, Issue 10 · 31 Oct 2010 · 7,936 accessesView PDFCite
Research ArticleOpen accessIn the keywordsTakagi-Sugeno Fuzzy Gains Scheduled PI Controller for Enhancement of Power System StabilityLokman H. Hassan, M. Moghavvemi, Haider A.F. MohamedProblem statement: Power system oscillations affect system stability and may lead to failure if not properly controlled. Approach: A Takagi-Sugeno Fuzzy Gains Scheduled Proportional and Integral (FGPI) controller was proposed for a Thyristor Controlled Series Capacitor (TCSC)-based stabilizer to enhance the power system stability. Linguistic rules and fuzzy inference mechanism are utilized to tune the controller parameters on-line in different … …American Journal of Applied Sciences, Vol. 7, Issue 1 · 31 Jan 2010 · 7,541 accessesView PDFCite