Design of a selective filter - antenna with low insertion loss and high suppression stopband for WiMAX applications

This paper presents a selective quasi–elliptic bandpass filter-antenna. The presented filter-antenna has a low insertion loss in the passband and relatively high stopband rejection. This structure consists of a quasi–elliptic bandpass filter direct coupled with patch antenna. The bandpass filter consists of four (λ/4) spiral square resonators. It has operates between (3.25–3.6) GHz so it is suitable for WiMAX applications. A CST Microwave Studio Suite software has used to simulate the filter-antenna circuit. The simulated results of the patch antenna and the results of the filter-antenna appears a good matching between the two circuits

Mechanism of melting in submonolayer films of nitrogen molecules adsorbed on the basal planes of graphite

URL:http://link.aps.org/doi/10.1103/PhysRevB.52.8515 DOI:10.1103/PhysRevB.52.8515The melting mechanism in submonolayer films of N2 molecules adsorbed on the basal planes of graphite is studied using molecular-dynamics simulations. The melting is strongly correlated with the formation of vacancies in the films. As the temperature increases, the edges of the submonolayer patch become atomically rough and vacancies are first created there. Then there is an onset temperature at which the vacancies penetrate into the patch. At an intermediate region of coverages ∼0.3-0.8 commensurate layers, there is sufficient free volume for the film to melt at that temperature. At higher coverages, ∼0.8-1.0 layers, a solid with defects is formed, and additional free volume must be created by higher energy mechanisms such as layer promotion for melting to occur; thus, the melting temperature rises with coverage. In contrast, for very small patches, the atomically rough zone penetrates the entire patch at a lower temperature where the film melts. The calculated melting temperatures are significantly lower than observed experimentally, indicating a severe fault in the potential model. A possible source of the discrepancy is identified.Our work was partially supported by the National Science Foundation under Grants Nos. DMR-9314235 (H.T.) and DMR-9120199 9L.W.B.) and by the Danish Natural Science Foundation (F.Y.H.)

العدد الثالث والرابع-6-1.doc

Abstract The aim of this study is clinical and pathological evaluation. of nodular thyroid Goiter Patients. Methods :-The Present prospective study pts of nodule thyroid goiter who were treated surgically was performed over a period from February 2004 -January 2007. clinical symptoms and signs, thyroid function test and Formalin fixed , Paraffin embedded blocks from 127 patients with thyroidctomy were included in this study. Results : -A total of 127 cases were included there is female predominance (77%), (73.1 %) cases were euthyriod, (24.2 %) cases hyperthyriedism and (3.1 %) hypothyriedism. the histopathological results of thyroid Nodules were ( 69.3 %) colloid nodular Goiter, (15.7%) toxic Nodules, 11.8 % thyroid tumors only (3.2 %) was hashiomito's thyrioditis. The Papillary carcinoma is the most common malignant tumor (3 cases) followed by follicular carcinoma (2 cases). Conclusion :