Recently, indoor positioning technology based on received signal strength in wireless networks are becoming more and more attractive. In this paper, we firstly introduced the experimental testbed in a typical office b...
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Recently, indoor positioning technology based on received signal strength in wireless networks are becoming more and more attractive. In this paper, we firstly introduced the experimental testbed in a typical office building. Then, we proposed the mechanism to improve the positioning accuracy by using five different filtering methods because of harsh multi-path environment and all kinds of disturbance in indoor areas. Thirdly, the experimental parameters of five filtering methods, called Limit Filter, Threshold Filter, Max Filter, MA Filter and Kalman Filter, were optimized and analyzed. Finally, we summarized the five filtering methods, and compared the performance of Limit Filter, Threshold Filter and Max Filter in detail. Experimental results demonstrated that the proposed Limit Filter andThreshold Filter can increase the accuracy in 3 meters of 91% to 98%.
A novel method based on radio frequency magnetron sputtering tailored to the deposition of low residual stress and adherent c-BN thin films on silicon substrates was developed. In this study, the effect of noble gas (...
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A novel method based on radio frequency magnetron sputtering tailored to the deposition of low residual stress and adherent c-BN thin films on silicon substrates was developed. In this study, the effect of noble gas (Kr, Ar, Ne and He) added in Ar gas during sputtering on the residual stress and the c-BN content has been investigated. As a result, it was found that the residual stress of c-BN thin film decreased with increasing the helium gas flow rate within argon gas.
A novel indoor positioning system based on received signal strength (RSS) in wireless networks with high accuracy is presented in this paper. The three improvement mechanisms, called signal strength filter, user locat...
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A novel indoor positioning system based on received signal strength (RSS) in wireless networks with high accuracy is presented in this paper. The three improvement mechanisms, called signal strength filter, user location filter and path tracking assistance, are employed to improve the positioning accuracy of the system. The comprehensive performance of the proposed system is analyzed in detail and compared with the Radar system. Experimental results demonstrate that the proposed system in this paper can improve 80% accuracy in 3 meters of Radar system to 93% in typical office building testbed. Therefore, the indoor positioning system presented in this paper has the advantages of high accuracy, low cost and easy expansibility, and it can be used to locate people and assets in the fields of logistics, healthcare, and manufacturing.
A research focus on semi-solid metal processing is the preparation of semi-solid slurry with non-dendritic microstructure. During the past several decades, people tended to obtain the non-dendritic structure by stirri...
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In present paper a new niobate materials Ba5LixTixNb10-xO30 were synthesized by doping Li+ in the system BaO- TiO2- Nb2O5 in millimeter wave field. X-ray diffraction (XRD) quantitative and scanning transition spectros...
In present paper a new niobate materials Ba5LixTixNb10-xO30 were synthesized by doping Li+ in the system BaO- TiO2- Nb2O5 in millimeter wave field. X-ray diffraction (XRD) quantitative and scanning transition spectroscopy (SEM) analysis were employed to study crystal structure and microstructure of reaction products. It was found that pure products could be obtained at temperature 900°, 8 min which is lower comparing with that by conventional method. The XRD data shown the crystal belongs to tetragonal tungsten bronze structure with space group P4bm. The grain size synthesized in millimeter wave field had smaller size, narrower distribution, better sinter-ability, and without hard agglomeration comparing whit that obtaining from conventional synthesis. At lower temperature Ba5LiTiNb9O30 is a tetragonal ferroelectric phase.
A high performance thermosetting epoxy resin crosslinkable at room temperature was obtained via directly moulding diglycidyl ether of bisphenol A（DGEBA） and flexibleα,ω-bisamino（n-alkylene）phenyl terminated poly...
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A high performance thermosetting epoxy resin crosslinkable at room temperature was obtained via directly moulding diglycidyl ether of bisphenol A（DGEBA） and flexibleα,ω-bisamino（n-alkylene）phenyl terminated poly（ethylene glycol）.The influences of the n-alkylene inserted in aminophenyl of flexible amino-terminated polythers（ATPE） on the mechanical properties,fractographs and curing kinetics of the ATPE-DGEBA cured products were *** results show that the insertion of n-alkylene group into the aminophenyl group of the ATPE,on one hand,can significantly increase the strain relaxation rate and decrease glass transition temperature of the ATPE-DGEBA cured products,resulting in slight decrease of the Young’s modulus and tensile strength,and significant increase of the toughness and elongation of the ATPE-DGEBA cured *** the other hand,it can remarkably enhance the reactivity of amine with epoxy,much accelerating the curing rate of the ATPE-DGEBA *** activation energy of DGEBA cured by BAPTPE,BAMPTPE and BAEPTPE was 53.1,28.5 and 25.4 kJ·mol;,*** as-obtained ATPE-DGEBA cured products are homogeneous, transparent,and show excellent mechanical properties including tensile strength and *** they are promising to have important applications in structure adhesives,casting bulk materials,functional coatings,cryogenic engineering, damping and sound absorbing materials.
Single-phase skutterudite compounds with highly relative density Ce0.8Fe4-x NixSb12(x=0-0.15) were prepared by combining melt spinning technique with spark plasma sintering. Their phase structure, microstructure and t...
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Single-phase skutterudite compounds with highly relative density Ce0.8Fe4-x NixSb12(x=0-0.15) were prepared by combining melt spinning technique with spark plasma sintering. Their phase structure, microstructure and thermoelectric properties were investigated. The result reveals that all samples show p-type conduction. When Fe was substituted by Ni, the electrical properties can be reduced to some extent, but the total thermal conductivity is decreased more evidently due to the reduction of κe caused by decreased carrier concentration and κL caused by alloying scattering. The maximum ZT value of about 0.73 is obtained at 800 K for the x=0.05 and x=0.10 samples, which was 18% higher than that of x=0 sample.
作者：
Pan YongJun潘勇军Xie HongQuan陈勇Chen Yong崔丽College of Material Science and Engineering
Wuhan Textile University Wuhan 430074 China 武汉纺织大学材料科学与工程学院 武汉 430073 Department of Chemistry Huazhong University of Science and Technology Wuhan 430074China 武汉理工大学复合材料国家重点实验室 武汉 430070 State key laboratory of advanced technology for materials synthesis and processingWuhan University of Technology Wuhan 430070 China
ZnO sub-millimeter crystals were synthesized by microwave heating from ZnO powders without any catalyst or transport agent. Zinc oxide raw materials were evaporated from the high-temperature zone in an enclosure and c...
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ZnO sub-millimeter crystals were synthesized by microwave heating from ZnO powders without any catalyst or transport agent. Zinc oxide raw materials were evaporated from the high-temperature zone in an enclosure and crystals were grown on the self-source substrate. The thermodynamics analysis method was used to estimate the partial pressure of gases in the chamber, which shows that the pressure of ZnO could be neglected entirely in the range of experiment temperature. The kinetics analysis was employed to estimate the growth rate in different conditions, which shows a remarkable temperature gradient and a high system temperature would enhance the growth rate. Optics photos reveal that these products are hexagon crystals with 0.2-0.3 mm in diameter and 0.5-1 mm in length. A vapor-solid mechanism is proposed to explain the growth process of ZnO crystals. The temperature distribution in microwave oven is mainly determined by properties of electric field and it is different from that of a conventional method.
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