1,721,068 research outputs found
High-performance air-buried microstrip lines and Ka-band branch line coupler
No full textAn air-buried microstrip line (ABMSL) is monolithically fabricated on a glass substrate using a cost-effective multilayer process. The insertion loss of the line is 0.07 dB/mm and it shows high-isolation characteristics between close transmission lines. Using the ABMSL, a branch-line coupler is monolithically fabricated. Because the ABMSL structure employs air-dielectric medium and ground conductor walls surrounding a strip conductor line, it is very effective for reducing dielectric loss and parasitic coupling between close transmission lilies over a high-frequency range. The fabricated branch-line coupler shows coupling and transmission losses of 3.6 and 3.9 dB, respectively, at the center frequency of 29 GHz. In the frequency range front 26 to 32 GHz (20% bandwidth), the return loss is below than 15 dB and the isolation is better than 14 dB. (c) 2005 Wiley Periodicals, Inc
Charge-transfer nature in luminescence of YNbO4 : Bi blue phosphor
No full textBismuth doped yttrium niobate (YNbO4:Bi) is a potential blue phosphor for field emission displays application. It is observed after introducing Bi ions that cathodoluminescence efficiency of YNbO4:Bi becomes lower than that of YNbO4. From the calculations of critical distance (R-C) of energy transfer and Huang-Rhys parameter (S-HR) of YNbO4:Bi, it is found that the energy transfer by a dipolar-type interaction is unlikely compared with that of a short-range interaction possible in the luminescence of YNbO4:Bi. Thus, it is believed that the luminescence property of YNbO4:Bi is mainly affected by the host lattice YNbO4 having self-luminescent NbO43- complex. By time-resolved spectroscopy, it is found that luminescence characteristics of activator Bi3+ in YNbO4:Bi shows a charge-transfer behavior. (C) 2001 American Institute of Physics.the Brain Korea 21 Project
Statistical processing of subjective listening test data for PSQ
No full textThe most fundamental method for judging the sound quality of a product is a subjective listening test. Because subjective tests are influenced by a variety of nuisance variables, systematic statistical data processing is required in order to assure the collection of reliable, reproducible, and statistically meaningful data. In this study, a statistical process consisting of four sequential steps is proposed for handling listening test data obtained by the magnitude estimation method. The first step is to ascertain the reproducibility of the evaluation of each subject for a given sample sound. The second step is to normalize the raw data by adjusting the scale range of individual ratings to fit into a predetermined global scale range. The third step involves determining if any differences exist among the tested sound signals. If differences among sounds are confirmed in the third step, the fourth step is to classify the sounds or sources into groups and to rank the groups. For this statistical process, the analysis of variance and Tukey's method were employed and loudspeakers, having the same dimension and structure but constructed with different diaphragm materials, were used as a model for evaluating sound quality. (C) 2003 Institute of Noise Control Engineering
A study on the adhesion and brightness of electrophoretically deposited ZnS:Ag, Cl phosphor by heat treatment condition
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