Papers by Keyword: Electromagnetic Waves (EMW)

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Authors: Guo Yan Dong, Ji Zhou
Abstract: Due to the existence of photonic bandgap derived from the periodical dielectric structure in wavelength scale, many novel optical phenomena can be demonstrated in photonic crystals (PhCs). Anomalous propagation of electromagnetic waves in X-band is demonstrated experimentally in a two-dimensional triangular lattice PhC. The experimental measurements of electric field are carried out in a near-field scanning system. The phenomena of anomalous refractions are observed and analyzed in respect of anisotropy of equal frequency surfaces in the PhC. The analysis results of numerical simulation are compared with the experimental measurements and good agreements are obtained.
Authors: Xiao Dong Tan, Lin Du, Pi Wei Song
Abstract: To solve the problem of digital debugging on bullet trans.A technology based on wireless communication in the detection and debugging for control system on bullet trains is proposed.The method is used to communicate between the wireless device on the host computer and the debugging equipment in the train, and the host computer can communicate with debugging equipment inside or outside the train.In the communication process, the environmental compartments need to be considered.The mathematical model is established based on the environment inside and outside the train for numerical calculation.The plane electromagnetic wave theory and the Fresnel formula is used for simulation analysis.The electromagnetic wave inside and outside the train is simulated with MATLAB.Finally the field test is carried on. the result shows that the technology can be effectively applied in the detection and debugging for control system on the train .
Authors: Mohd Hanafiah Mat Jamlus, Zainal Ambri Abdul Karim
Abstract: This paper presents the findings in attaining soot oxidation temperature by using carbon steel coils exposed to electromagnetic waves. Soot are unburned carbon product in the exhaust gases during the combustion of diesel fuel, which are subjected to stringent emission regulations due to its harmful properties. The unburned carbon can be oxidised by heating as after-treatment strategy but in order for the oxidation to occur, it would require a temperature of not less than 600°C. In the present work, eight heating elements made from various carbon steel coil sizes were exposed to electromagnetic waves in the microwave oven cavity which heats up the coils to the oxidation temperature. Electromagnetic waves heating utilises electromagnetic radiation to induce electric field in a conductive material that causes the material to be heated. The microwave oven used has a power rating of 1000 W, with a microwave range of 2450 Mhz. Measurement of coils temperature and exposure time to electromagnetic waves were recorded and analysed. The results showed that only the coils with bigger coil loop size, i.e. 20 mm and lowest number of turns, i.e. 10 turns attained the threshold temperature of 600°C, while smaller diameter coil would accelerate the rate of heating. The findings from the research work are significant facts in the future development of in-situ exhaust gas after treatment system in reducing soot emissions.
Authors: Gi Hwan Kang, Sung Hoon Kim
Abstract: The carbon coils (d-CCs) having the diverse geometries were deposited on Al2O3 substrate by continuous injection of SF6 in C2H2 source gas under the thermal chemical vapor deposition system. d-CCs with polyurethane (PU) composites (d-CCs@PU) were fabricated by dispersing d-CCs in PU solvent with dimethylformamide (DMF) additive. The electromagnetic wave shielding properties of d-CCs@PU composites were investigated in the frequency range of 0.25-1.5 GHz. The shielding effectiveness (SE) of d-CCs@PU composites were measured and discussed according to the weight percent of d-CCs in CCs@PU composites and the thickness of d-CCs@PU composites layers. Based on these results, we discussed the shielding properties of d-CCs@PU composites and the main mechanism of the SE in this work.
Authors: Xiang Jiang Li, Jing Fan
Abstract: With the popularity of wireless communication systems, the question of radio signal coverage is getting more and more attentions in corridor for high-rise buildings. Using loss rectangular dielectric waveguide theory, the attenuation of electromagnetic wave transmission rate is calculated in theory. Because of the complexity of electromagnetic waves propagation conditions, site measurement of transmission loss is done in band 210MHz, 460MHz, 1.2GHz and 2.0GHz. Measurement results show that the wireless signal transmission loss rate is similar with the calculation of loss rectangular dielectric waveguide theory on the trend
Authors: Guang Ke Xu, Wei Wei Zhang, Zhen Hua Zhu, Nan Wang, Fu Qiang Zhao
Abstract: UHF electromagnetic waves radiated by PD in GIS can range from several hundreds of MHz to several GHz. FDTD method is usually used to simulate the characteristics of the UHF electromagnetic waves. Compared with the traditional ideal Gaussian pulses in simulation, one equivalent PD mathematical model based on the actual measure PD sources was considered to simulate the propagation characteristics. Time domain and frequency domain spectrum of signals excited by the two PD sources were studied to analyze the propagation characteristics. It can draw the conclusions that each insulator detect leads to each electromagnetic and its time domain and frequency domain spectrum. So it is recommended to use equivalent PD mathematical model to simulator the propagation characteristics.
Authors: Alongorn Promtee, Churairatchinda Akkanit
Abstract: This research aims to develop instruction model using cognitive learning theories on electromagnetic field and wave for undergraduate of electrical engineering program. The new instruction model called FATAC model was developed. It consists of 5 steps as; 1) Find 2) Adjust 3) Teach 4) Actions and 5) Conclusion. The content of dissertation has 3 Units; 1) Maxwell equations and electromagnetic wave are direct variation with time 2) Microwave planar and 3) Poynting vector and wave propagation. Thirty students of level 3 in technical education, rajamangala university of technology isan, khonkaen campus were a sampling group. Tools of dissertation included lesson plans, learning media as powerpoint presentation, electromagnetic wave propagation simulation program, wave propagation demonstration set, and filed strength meter. The research results consisted of; 1) The opinion on the FATAC model was high level (=4.21,S.D.=0.48). 2) The learning effectiveness of the instructional model was 76.15/76.73 (higher than 75/75 of the hypothesis). 3) The quality of instruction package by experts was high level (=4.27 ,S.D=0.62) and 4) The mean of satisfaction of the sampling group was high level (=4.23 ,S.D=0.57). Therefore, in conclusion, instruction model using cognitive learning theories on electromagnetic wave and propagation for undergraduate of electrical engineering program can be applied for electromagnetic theory subject and high efficiency.
Authors: Yoshihisa Fujii, Yuko Fujiwara, Yoshiyuki Yanase, Takuro Mori, Tsuyoshi Yoshimura, Masao Nakajima, Hiroki Tsusumi, Mitsunori Mori, Hiroshi Kurisaki
Abstract: A nondestructive and small FMCW radar apparatus for scanning of the wooden wall to evaluate inner structure and biodegradation progressed in the wall was developed, and the performance of the apparatus was investigated. The allocations and the properties of the construction members in the wall, such as wooden posts and beams, metal plate connectors and insulating materials was recognized as 2D and 3D images. The moist area of more than 50% in moisture content in the wall was also recognized, and this suggests that the area of potentiality of biodegradation such as fungal and insect attacks in the wall can be detected by this apparatus. The feasibility of the apparatus to evaluate of the loss in the wood substance caused by the bio-degradation was also confirmed.
Authors: Ling Fei Cheng, Jie Li, Li Li Zhang
Abstract: All aspects of coal mining will emit large quantities of dust to the tunnel. There are many factors of the floating dust in the tunnel affecting the propagation of electromagnetic waves, such as frequency, consistency and droplet. Combining with the formula in relevant references, this paper uses software to simulate and obtains relevant characteristic curves. Finally, it is clear that the attenuation of propagation increases with the frequency of electromagnetic waves, dust consistency, droplet and temperature also affect the propagation characteristic. Obviously, these factors almost weaken the propagation of electromagnetic waves
Authors: Hassan Soleimani, Noor Rasyada Ahmad Latiff, Noorhana Yahya, Hasnah Mohd Zaid, Maziyar Sabet, Beh Hoe Guan, Kean Chuan Lee
Abstract: Usage of magnetic materials is not unusual in oil and gas research, specifically in enhanced oil recovery (EOR) where various magnetic micro-and nanoparticles were used to enhance sweep efficiency, reducing interfacial tension and heat generation. Magnetic nanoparticles which are activated by a magnetic field are anticipated to have the ability to travel far into the oil reservoir and assist in the displacement of the trapped oil. In this work, magnetic Fe2O3-Al2O3 nanocomposite was synthesized and characterized for its morphological, structural and magnetic properties. At an annealing temperature of 900°C, this nanomaterial starts to exhibit magnetization as the composite structure crystallizes to the stable Fe2O3 and Al2O3. Subsequently, dispersion of the 0.01 wt% Fe2O3-Al2O3 nanocomposite in distilled water was used for displacement tests to validate its feasibility to be applied in EOR. In the displacement test, the effect of electromagnetic waves on the magnetization of Fe2O3-Al2O3 nanofluid was also investigated by irradiating a 13.6 MHz square wave to the porous medium while nanofluid injection is taking place. In conclusion, an almost 20% increment in the recovery of oil was obtained with the application of electromagnetic waves in 2.4 pore volumes (PV) injection of Fe2O3-Al2O3 nanofluid.
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