a direct conversion modulator-demodulator with even harmonic mixers with emphasis on noise analysis is presented. the circuits consist of even harmonic mixers (ehms) realized with antiparallel diode pairs (apdps). we evaluate the different levels of i/q imbalances and dc offsets and use signal space concepts to analyze the bit error rate (ber) of the proposed transceiver using m-ary qam schemes...

the runoff generation and soil erosion in the kechik watershed, golestan province, was assessed, using a designed and constructed portable rainfall simulator. treatments were applied on different land-uses, slopes and aspects as the most influential factors. results showed that land-use significantly affected runoff generation (13.35 l, 6.9 l, and 4.12 l, respectively for agriculture, forest an...

the direct conversion of methane to c2 hydrocarbons, in a quartz tube reactor enforced by a dc corona discharge, was investigated at atmospheric pressure. the process was carried out in the presence of metal oxide catalysts of mn/w/sio2, mn/w/sio2 (tetraethyl orthosilicate, teos), and mn/w/cnt (supported on carbon nanotubes). the total yield to c2 hydrocarbons in the presence of metal oxide cat...

how to cite this article: bidaki r, zarepur e, akrami m, nadi sakhvidi m. functional neurological symptom disorder: mismanagement, misdiagnosis, chronic cough following sexual abuse; a rare case report. iran j child neurol. spring 2016; 10(2):90-92. abstract objective conversion disorder (cd) is a mental disorder in which patient displays neurological symptoms such as blindness, mutism, paralys...

statement of problem: the degree of conversion depends on the material composition, light source properties, distance from light source, light intensity, curing time, and other factors such as shade and translucency. objectives: in the present study, we evaluated the effects of different light- curing modes and shades of methacrylate and silorane-based resin composites on the degree of conversi...

A photonic crystal-based TE to TM polarization converter for integrated optical communication is proposed in this paper. The photonic crystal consists of air circular-holes in slab waveguide. The radius of holes are determined to be 291nm having lattice constant of 640nm using the gap map and band diagram. The polarization converter is composed of an InGaAsP triangular-shaped waveguide on SiO2 ...

the role of nickel as catalyst on the conversion of methane and ethylene in a gas phase flow reactor in the absence of oxygen is studied. in this study, nickel in its different forms is used as catalyst. the role of pressure, flow rate, and temperature on the conversion of feed gases is investigated. the experiments have been carried out in the presence and absence of the catalysts to measure t...

Manganese oxide catalyst promoted with sodium and supported on silica exhibits fairly good activity and selectivity towards the synthesis of ethylene from methane at the optimum operating conditions. Methane and oxygen were fed into a tubular fixed bed reactor packed with catalyst under atmospheric pressure. The effects of temperature, residence time and feed composition on conversion, selectiv...

We examine the role low-price guarantees allegedly play in supporting supracompetitive prices. We find that when firms can commit to matching or beating any lower price announced by a competitor, all Nash equilibria yield Bertrand selling prices. This result casts doubt on the robustness of the conclusions of models which restrict attention to meet-the-competition clauses only. JEL Classificati...

The hypothesis that three separate mutations to the βS -globin gene have occurred in Africa in challenged. The distributions of the βS and other β-globin haplotypes and a simulation of the diffusion of the βS gene are presented and argued to be more in accord with the rapid diffusion of a single mutant that by recombination and gene conversion now occurs on several different haplotypes.