The capability test of electronic tag
This paper introduces problems of electronic tag in actual application and the essentiality of capability test for electronic tag. We have established a test platform which is based on radio frequency and worked out some related schemes, which has laid the experimental foundations for further researching environmental influence factor in electronic tag in future.
On the read zone analysis of radio frequency identification systems with transponders oriented in arbitrary directions
One of the most important characteristics of a Radio Frequency IDentification (RFID) system is its "read zone", which is defined as the volume inside which the base station can communicate with the transponders (or, tags). This paper presents a systematic approach to analyzing the read zone of an RFID system where the base station antennas are a pair of switchable circularly polarized antennas and the transponder antennas are linearly-polarized and oriented in arbitrary directions.
Effect of superficial gas velocity on the particle temperature distribution in a fluidized bed with heat production
The heat transfer behavior of particles and gas in an olefin polymerization fluidized bed was numerically analyzed using an in-house developed 3-D computational fluid dynamics discrete element model (CFD-DEM). First the implementation of the model was verified by comparing simulation results with analytical results. A constant volumetric heat production rate was implemented in the particle energy equation to mimic the heat production due to the polymerization reaction. It was found that the probability density function (PDF) of the particle temperature becomes more homogeneous with increasing superficial gas velocity. Furthermore, instantaneous snapshots of the thermal driving force (the difference between the single particle temperature and bed-average gas temperature, Tp− ) for different heat production rates provide detailed insight in the particle temperature distribution inside the fluidized bed. The time- and bed-averaged particle convective heat transfer coefficient, which was calculated by Gunn׳s correlation, was found to be independent of the superficial gas velocity. This is explained by the fact that the relative velocity of gas and particles in the emulsion phase, where most of the particles and gas interact, is hardly influenced when increasing the gas superficial velocity. From the spatial distribution of Nusselt number, it becomes apparent that the high heat transfer regions are found in the wake of rising bubbles, whereas low heat transfer rates are found in the clouds of the bubbles.