Taguchi robust design was used for optimization of direct precipitation reaction conditions in order to simple and fast synthesis of manganese carbonate nanoparticles. Manganese carbonate nanoparticles were synthesized in this study by addition of manganese ion solution to the aqueous carbonate reagent. Effects of several reaction variables, such as manganese and carbonate concentrations, flow rate of reagent addition and temperature on particle size of prepared manganese carbonate were investigated. The significance of these parameters in tuning the size of manganese carbonate particles was quantitatively evaluated by analysis of variance. The results showed that manganese concentration and carbonate concentration in the solutions and also flow rate have significant effects in preparation of manganese carbonate nanoparticles. Also, optimum conditions for synthesis of manganese carbonate nanoparticles via precipitation reaction were proposed. Analysis of variance showed that under the optimum condition, the size of manganese carbonate nanoparticles will be about 54 ± 12 nm. In another part of this study, solid state thermal decomposition reaction of precursor was used for preparation of Mn2O3 nanoparticles. The results showed that Mn2O3 nanoparticles synthesized via thermal decomposition of manganese carbonate nanoparticles have average size of 90 nm. 相似文献
The use of wireless sensor networks has significantly increased in the last decade. These networks consist of a large number of small sensors, which are efficient tools for data collection from different environments. The data collected by these sensors will be usually transmitted to a base station that will provide the end user’s data. In order to improve scalability of such networks, sensor nodes can be grouped into non-overlapped clusters. These clusters create a hierarchical design in wireless sensor networks that leads to better energy utilization and thus increase the network’s lifetime. Using validity indexes and meta-heuristic algorithms are common ways to improve performance of clustering. In this paper, we provide a new validity index called ASCS by enhancing the Chou and Su (CS) validity index, and improve the performance of the meta-heuristic algorithms for clustering using this new validity index as their objective functions. Differential evolution and harmony search are two algorithms that will be used for this purpose. The experimental results show the better performance of ASCS index comparing to Davies and Bouldin (DB) and CS validity indexes in determining appropriate number of clusters and determining proper clusters’ members.
Three-way data obtained from different pulse heights of differential pulse voltammetry (DPV) was analyzed using multivariate curve resolution by alternating least squares (MCR-ALS) algorithm. Differential pulse voltammograms of tryptophan were recorded at a gold nanoparticles decorated multiwalled carbon nanotube modified glassy carbon electrode (GCE/MWCNTs-nanoAu). The determination of tryptophan was performed even in the presence of unexpected electroactive interference(s). Both the simulated and experimental data were non-bilinear. Therefore a potential shift algorithm was used to correct the observed shift in the data. After correction, the data was augmented and MCR-ALS was applied to the augmented data. A relative error of prediction of less than 8% for the determination of the simulated analyte of interest and tryptophan in synthetic samples indicated that the methodology employing voltammetry and second-order calibration could be applied to complex analytical systems. 相似文献
Wireless Personal Communications - Due to using wireless sensor nodes (WSNs) in inaccessible areas and applying limitations in making nodes to reduce costs, these networks are prone to faults. The... 相似文献
In connection with our research program directed toward the synthesis of anthraquinones by new catalyst, we achieved a new method for preparation of some anthraquinone derivatives from the reaction of aromatic compounds with phthalic anhydride in the presence of silica sulfuric acid (SSA). The advantages of this method are availability of starting materials, simplicity of the reaction, reusability of catalyst and purity of products. In this reaction, the products were obtained via easy work-up in high yields and short reaction times. The structures of products were assigned by physical data and spectroscopic methods. 相似文献
In this article, a low-power and energy-efficient hybrid full adder circuit is proposed, which is implemented based on multi-threshold NAND and NOR gates and transmission gate multiplexers. In order to implement this circuit, carbon nano tube field effect transistors are utilised. For evaluating the proposed design, comprehensive simulations are performed with regard to the most important aspects power, delay and power-delay product. The results are presented and displayed the superiority of the proposed cell in different voltage levels, load conditions, temperatures and robustness against process variations. 相似文献
Wireless sensor networks (WSNs) have been vastly employed in the collection and transmission of data via wireless networks. This type of network is nowadays used in many applications for surveillance activities in various environments due to its low cost and easy communications. In these networks, the sensors use a limited power source which after its depletion, since it is non‐renewable, network lifetime ends. Due to the weaknesses in sensor nodes, they are vulnerable to many threats. One notable attack threating WSN is Denial of Sleep (DoS). DoS attacks denotes the loss of energy in these sensors by keeping the nodes from going into sleep and energy‐saving mode. In this paper, the Abnormal Sensor Detection Accuracy (ASDA‐RSA) method is utilized to counteract DoS attacks to reducing the amount of energy consumed. The ASDA‐RSA schema in this paper consists of two phases to enhancement security in the WSNs. In the first phase, a clustering approach based on energy and distance is used to select the proper cluster head and in the second phase, the RSA cryptography algorithm and interlock protocol are used here along with an authentication method, to prevent DoS attacks. Moreover, ASDA‐RSA method is evaluated here via extensive simulations carried out in NS‐2. The simulation results indicate that the WSN network performance metrics are improved in terms of average throughput, Packet Delivery Ratio (PDR), network lifetime, detection ratio, and average residual energy. 相似文献