Chemometrics-Enhanced Micelle-Mediated Extraction Spectrophotometric Method for Simultaneous Determination of Cu<Superscript>2+</Superscript> and Zn<Superscript>2+</Superscript> in Medicinal Plant,Rice and Water Samples Using Continuous Wavelet Transform

A new micelle-mediated extraction method for the pre-concentration of trace amounts of Cu²⁺ and Zn²⁺ as a prior step to their simultaneous spectrophotometric determination has been developed in various samples. The analytes were complexed with new synthesized ligand 4,4′-((4-chlorophenyl)methylene)bis(1,3-diphenyl-1H-pyrazol-5-ol) (CPBMPY) and Triton X-100 was added as a extraction agent. The optimal reaction and extraction conditions were optimized and the analytical characteristics of the method were obtained. The detection limit of the method was 0.90 and 0.30 ng mL^?1 for Cu²⁺ and Zn²⁺, respectively. Continuous wavelet transformation (CWT) of visible spectra as a very simple and accurate method was developed for the simultaneous determination of binary mixtures of Cu²⁺ and Zn²⁺ ions. A zero-crossing technique was applied on the transformed signals and the constructed calibrations were tested by analyzing the composition of the different binary mixtures. The proposed procedure successfully was applied to analysis of water, rice, and medicinal plant and reference material samples. The amounts of metal ions obtained by the proposed methods were in good agreement with those obtained by Graphite furnace atomic absorption spectrometry.     

Molecular dynamics study of a macromolecular model of hydrous sodium aluminosilicate geopolymer with charge balancing by extra-structural aluminum for prediction of its properties

Geopolymer is a material with unique properties and has various uses. This substance is mainly amorphous, and its qualitative characteristics are related to its binder phase that is called the hydrous sodium aluminosilicate geopolymer. The molecular structural model of this geopolymer includes ${\text{Q}}^4\left(4\text{Al}\right),{\text{Q}}^4\left(3\text{Al}\right),{\text{Q}}^4\left(2\text{Al}\right)$, and ${\text{Q}}^4\left(1\text{Al}\right)\text{Si}$ units, which have been balanced in terms of electric charge by extra-framework $\text{Al}$ and ${\text{Na}}^{+}$ ions. In this study, we calculated the density, Young's modulus, and RDF curve of the geopolymer from the molecular dynamics simulation. The results of the simulation were in good agreement with the results of the laboratory obtained from several studies.     

Capacity enhancement in coherent optical MIMO (COMIMO) multimode fiber links

In this paper, we study a coherent optical MIMO (COMIEMO) multi-mode fiber link proposed for enhancing the fiber information capacity. We examine the statistical characterization of the equivalent MIMO channel and the improvement in the fiber capacity due to MIMO transmission. It is shown that the equivalent channel behaves similarly to a complex Gaussian MIMO channel, suggesting that the available results on wireless MIMO communication systems can be applied to optical fiber links for capacity enhancement.     

Coherent optical MIMO (COMIMO)

We present a multiple-input multiple-output (MIMO) optical link based on coherent optics and its ability to exploit the inherent information capacity of multimode fiber. A coherent implementation differs from previous work in optical MIMO by allowing the system to tolerate smaller modal delay spreads, because of a much larger carrier frequency, and yet maintain the necessary diversity needed for MIMO operation. Furthermore, we demonstrate the use of MIMO adaptive equalization to mitigate intersymbol interference when exceeding the bandwidth-length product of the link. The impact of phase noise is studied with numerical simulation.     

Immobilisation of cobaltferritin onto gold electrode based on self-assembled monolayers

The iron storage protein, ferritin, has a cavity of ～7?nm in diameter in which iron is oxidised and stored as a hydrated oxide core. Electron transfer is known to be an important step in the sequestering of iron by cellular ferritin. The cavity was used as a nanocontainer to grow cobalt nanoparticles. The immobilisation of ferritin on the electrode surface is essential for various bioelectronic applications. A cobaltferritin-immobilised electrode based on self-assembled monolayer (SAM)-modified gold electrode was developed. The cobaltferritin-immobilised SAM-modified electrode was characterised by electrochemical and atomic force microscopy (AFM) techniques. The results indicated that cobaltferritin was selectively immobilised onto succinimidyl alkanedisulfide-modified Au electrode by the covalent interaction between cobaltferritin and the terminal functional groups of the SAMs. The cobaltferritin immobilised modified electrode showed a direct electron transfer reaction between cobaltferritin and the electrode. The electrochemically regulated uptake and release of cobalts for cobaltferritin immobilised on the SAMs were demonstrated. The results obtained in this study indicate that cobaltferritin has potential for a biomaterial in nanoscale synthesis for potential magnetic, catalytic and biomedical-sensing applications.     

Joint compensation of IQ imbalance and phase noise in OFDM wireless systems

Physical impairments like IQ imbalance and phase noise can cause significant degradation in the performance of wireless communication systems. In this paper, the joint effects of IQ imbalance and phase noise on OFDM systems are analyzed, and a compensation scheme is proposed to improve the system performance in the presence of IQ imbalance and phase noise. The scheme consists of a joint estimation of channel and impairment parameters and a joint data symbol estimation algorithm. It is shown both by theory and computer simulations that the proposed scheme can effectively improve the signal-to-noise ratio at the receiver. As a result, the sensitivity of OFDM receivers to the physical impairments can be significantly lowered, simplifying the RF and analog circuitry design in terms of implementation cost, power consumption, and silicon fabrication yield.     

Network-based wireless location: challenges faced in developing techniques for accurate wireless location information

Wireless location refers to the geographic coordinates of a mobile subscriber in cellular or wireless local area network (WLAN) environments. Wireless location finding has emerged as an essential public safety feature of cellular systems in response to an order issued by the Federal Communications Commission (FCC) in 1996. The FCC mandate aims to solve a serious public safety problem caused by the fact that, at present, a large proportion of all 911 calls originate from mobile phones, the location of which cannot be determined with the existing technology. However, many difficulties intrinsic to the wireless environment make meeting the FCC objective challenging. These challenges include channel fading, low signal-to-noise ratios (SNRs), multiuser interference, and multipath conditions. In addition to emergency services, there are many other applications for wireless location technology, including monitoring and tracking for security reasons, location sensitive billing, fraud protection, asset tracking, fleet management, intelligent transportation systems, mobile yellow pages, and even cellular system design and management. This article provides an overview of wireless location challenges and techniques with a special focus on network-based technologies and applications.     

Realization of Flexible Plasma Display Panels on PET Substrates

DC plasma display panels are fabricated on flexible polyethylene terephtalate (PET) substrates. Each pixel consists of laterally placed anode and cathode electrodes. All electrical elements are formed on a single PET substrate, whereas a second substrate is needed to encapsulate the panel. Silver is used as the metal for each electrode and standard photolithography is used to form each cell. A 150-/spl mu/m-thick layer of a UV-curable polymeric adhesive was used to form barrier ribs to both electrically isolate neighboring cells and to encapsulate the plasma. Conversion of vacuum UV into visible light is possible by blast-embedding of proper phosphor grains into the top substrate. The current-voltage and turn-on voltage versus pressure characteristics are examined. Effect of curvature on turn-on voltage is addressed.     

An uplink DS-CDMA receiver using a robust post-correlation Kalman structure

Kalman filtering has been proposed in the literature for wireless channel estimation, however, it is not sufficiently robust to uncertainties in the channel auto-correlation model as well as to multiple access interference (MAI). This paper presents a receiver structure for direct-sequence code-division multiple-access (DS-CDMA) systems by using robust Kalman estimation and post-correlation (i.e., symbol rate) processing for channel estimation. The proposed structure is also generalized to incorporate multiple-antenna combining and interference cancellation techniques. The resulting receiver outperforms earlier structures in the presence of channel modeling uncertainties, MAI, and low-received signal-to-noise ratio. The enhancement in performance is achieved at the same order of complexity as a standard Kalman-based receiver.     

Design and VLSI implementation for a WCDMA multipath searcher

The third generation (3G) of cellular communications standards is based on wideband CDMA. The wideband signal experiences frequency selective fading due to multipath propagation. To mitigate this effect, a RAKE receiver is typically used to coherently combine the signal energy received on different multipaths. An effective multipath searcher is, therefore, required to identify the delayed versions of the transmitted signal with low probability of false alarm and misdetection. This paper presents an efficient and novel WCDMA multipath searcher design and VLSI architecture that provides a good compromise between complexity, performance, and power consumption. Novel multipath searcher algorithms such as time domain interleaving and peak detection are also presented. The proposed searcher was implemented in 0.18 /spl mu/m CMOS technology and requires only 150 k gates for a total area of 1.5 mm/sup 2/ consuming 6.6 mw at 100 MHz. The functionality and performance of the searcher was verified under realistic conditions using a channel emulator.