this work is focused on synthesis of sio2- cnt hybrides via sol-gel method. homogeneous distribution of carbon nanotubes within silicon matrix was obtained by mixing the functionalized carbon nanotube (cntcooh) with active silicic acid followed by titration to the solution of sodium silicate (na2sio3) under the average temperature condition of 80?c. different ratios of multi-walled carbon nanot...

in this work, a novel method is described for the preconcentration of pb2+, cd2+ and zn2+ ions in environmental samples using uniform silanized mesopor (lus-1) functionalized by ethylenediamine groups as a new extractant. the determination of ions is done by inductively coupled plasma optical emission spectrometry (icp-oes). the extraction time and efficiency, ph and amount of adsorbent, minimu...

In order to identify ecotyps of field binweed (Convolvulus arvensis L.), seeds from eight proviences, including 125 populations were gathered and sent to Weed Research Department of Plant Pests & Diseases Research Institute, Tehran, Iran. These seeds planted in a uniform environment condition in Tehran. On the base of 24 morphological and physiological characteristics of seedling that derived f...

We consider the one-dimensional bin packing problem under the discrete uniform distributions U{j, k}, 1 ≤ j ≤ k − 1, in which the bin capacity is k and item sizes are chosen uniformly from the set {1, 2, . . . , j}. Note that for 0 < u = j/k ≤ 1 this is a discrete version of the previously studied continuous uniform distribution U(0, u], where the bin capacity is 1 and item sizes are chosen uni...

Given the user distribution in a cell, we investigate the two problems of how to appropriately sectorize the cell such that we minimize the total received power and the total transmit power of all the users, while giving each user acceptable quality of service in both cases. For the received power optimization problem, we show that the optimum arrangement equalizes the number of users in each s...