A binomially distributed photonic bandgap structure (PBGS) and its application to bandpass filter

Conventional hole‐patterned photonic bandgap structures (PBGSs) yield distinct and wide stopband, but suffer from a significant ripples in the passband beyond the optimized filling factor (FF) of 0.25. Binomial distribution in PBGSs can yield improved performance beyond this value. The optimum FF of binomially distributed PBGSs has been ivestigated at multifrequencies in the X‐band, namely, at 9, 10.5, and 12 GHz. It can be seen that 0.4 may be considered as the optimum FF for binomially distributed PBGSs at different frequencies within X‐band operations. Finally, binomially PBGSs with this optimium FF are applied in a bandpass filter (BPF) for suppresing the intrinsic spurious harmonics of a BPF. The various experimental investigations reveal that the variation in number of PBG elements and their locations affect the performance of harmonic suppression. Binomially distributed PBGSs are found to be potential candidate to suppress the harmonic signal and to improve the return‐ and insertion‐loss bandwidths. © 2006 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2006.     

Planar electromagnetic bandgap structures

This article presents various novel and conventional planar electromagnetic bandgap (EBG)‐assisted transmission lines. Both microstrip lines and coplanar waveguides (CPWs) are designed with circular, rectangular, annular, plus‐sign and fractal‐patterned EBGs and dumbbell‐shaped defected ground structure (DGS). The dispersion characteristics and the slow‐wave factors of the design are investigated. © 2006 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2006.     

Electrocoagulation (EC)--science and applications

Although electrocoagulation is an evolving technology that is being effectively applied today for wastewater treatment, the paucity of scientific understanding of the complex chemical and physical processes involved is limiting future design and hindering progress. The objective of this review through a survey of the literature is to bring the chemistry and physical processes involved into perspective and to focus attention on those areas critically needing research.     

Intercalation of kaolinite under hydrothermal conditions

Intercalation of kaolinite with dimethylsulphoxide (DMSO) was carried out under hydrothermal conditions using a Parr bomb. The intercalated complex has been characterized by X-ray diffraction (XRD), Fourier transform-infrared spectroscopy (FT-IR) and thermogravimetric analysis techniques. It was found that the intercalation reaction is completed in 20 min and a high yield, 90%, of kaolinite/DMSO intercalate was obtained. An expansion of the original c-axis spacing of 0.714 nm in kaolinite to 1·124 nm, as a result of incorporation of DMSO molecules into the kaolinite interlayers, has been observed by XRD studies. FT-IR analyses of the intercalated complex have established the nature of interactions between the host structures and the incoming DMSO molecules. The hydrothermal method of intercalation developed in this study can also be used for other systems.     

Body radioactivity and radiation dose from 40K in Bangladeshi subjects measured with a whole-body counter

A group of subjects of Bangladeshi adults from both sexes were studied for internal radioactivity and effective dose by measuring the whole-body activity of naturally occurring (40)K using a whole-body counter. The mean activity concentration in the whole body and effective dose due to naturally occurring (40)K for the average male were found to be 2.0 +/- 0.4 Bq.g(-1) and 100 +/- 26 microSv.y(-1), respectively and those for the average female were 1.7 +/- 0.3 Bq.g(-1) and 100 +/- 20 microSv.y(-1), respectively. The mean activity concentration in the whole body and effective dose for both sexes were 1.9 +/- 0.4 Bq.g(-1) and 100 +/- 25 microSv.y(-1), respectively. The effective dose from (40)K for subjects is below the value reported by the UNSCEAR.     

Journey of scene text components recognition: Progress and open issues

In computer vision, scene text component recognition is an important problem in end-to-end scene text reading systems. It involves two major sub-problems - segmentation of such components into scene characters and classification of segmented characters into known character classes. Significant attention and increasingly focused research efforts are being put forth and reasonable progress in this field has already been made, though a diversity of challenges like background complexity, variety of text appearances, noise, blur, distortion and various other degradation and deformation issues are still left to address. In this paper, we present (i) a detail survey of scene component segmentation and/or recognition methods reported so far in literature, (ii) related datasets available for quantitative evaluation and benchmarking segmentation and/or recognition performance, (iii) comparative results and analysis over the reported methods, and (iv) discussion on open areas to be looked into in order to achieve the desired goal of end-to-end scene text recognition. Moreover, this paper provides an acceptable reference for researcher in the area of scene text components segmentation and recognition.

     

Effect of Co substitution on the structural and optical properties of ZnO nanoparticles synthesized by sol-gel route

Co doped ZnO nanoparticles were synthesized by sol-gel method and characterized by X-ray diffraction (XRD), Transmission electron microscopy (TEM), Energy dispersive X-ray analysis (EDAX), UV-Visible absorption spectroscopy and Fourier transform infrared spectroscopy (FTIR). XRD analysis revealed the formation of single phase structure of all samples which was further supported by FTIR data. With the increase in Co concentration from 0% to 5%, crystallite size was observed to vary from 27.1 to 21.3 nm. It suggests the prevention of crystal growth as a result of Co doping in ZnO. It was also evident from the absorption spectra that the absorbance tends to increase with the increase in dopant concentration. Optical band gap was found to increase slightly with the increase in Co content, confirming the size reduction as a result of Co doping.