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Modification of the structural and electrical properties of graphene layers by Pt adsorbates
Iqbal, M Waqas,Iqbal, M Zahir,Khan, M Farooq,Jin, Xiaozhan,Hwang, Chanyong,Eom, Jonghwa TaylorFrancis 2014 SCIENCE AND TECHNOLOGY OF ADVANCED MATERIALS Vol.15 No.5
<P>The properties of graphene are strongly affected by metal adsorbates and clusters on graphene. Here, we study the effect of a thin layer of platinum (Pt) metal on exfoliated single, bi- and trilayer graphene and on chemical vapor deposition-grown single-layer graphene by using Raman spectroscopy and transport measurements. The Raman spectra and transport measurements show that Pt affects the structure as well as the electronic properties of graphene. The shift of peak frequencies, intensities and widths of the Raman bands were analyzed after the deposition of Pt with different thicknesses (1, 3, 5 nm) on the graphene. The shifts in the G and 2D peak positions of the Raman spectra indicate the n-type doping effect by the Pt metal. The doping effect was also confirmed by gate-voltage dependent resistivity measurements. The doping effect by the Pt metal is stable under ambient conditions, and the doping intensity increases with the increasing Pt deposition without inducing a severe degradation of the charge carrier mobility.</P>
Edge Oxidation Effect of Chemical-Vapor-Deposition-Grown Graphene Nanoconstriction
Iqbal, Muhammad Waqas,Iqbal, Muhammad Zahir,Jin, Xiaozhan,Hwang, Chanyong,Eom, Jonghwa American Chemical Society 2014 ACS APPLIED MATERIALS & INTERFACES Vol.6 No.6
<P>The edge oxidation effects of chemical-vapor-deposition-grown graphene devices with nanoconstrictions of different sizes are presented. The effects of edge oxidation on the doping level of a nanoconstriction graphene device were identified by Raman spectroscopy and using the back-gate-voltage-dependent resistance. Strong p-type doping was observed as the size of nanoconstriction decreased. The Dirac point of the graphene device shifted toward positive voltage, and the positions of the G and 2D peaks in Raman spectroscopy shifted toward a higher wave number, indicating the p-type doping effect of the graphene device. p-type doping was lifted by deep-ultraviolet light illumination under a nitrogen atmosphere at room temperature. p-type doping was restored by deep-ultraviolet light illumination under an oxygen atmosphere at room temperature. Edge oxidation in the narrow structures explains the origin of the p-type doping effect widely observed in graphene nanodevices.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/aamick/2014/aamick.2014.6.issue-6/am405885c/production/images/medium/am-2013-05885c_0008.gif'></P>
DC Motor Speed Control via FoPID-Controllers
Iqbal M. Batiha,Shaher Momani,Radwan M. Batyha,Iqbal H. Jebril,Duha Abu Judeh,Jamal Oudetallah 한국지능시스템학회 2024 INTERNATIONAL JOURNAL of FUZZY LOGIC and INTELLIGE Vol.24 No.1
This work aims to propose several designs for controlling the DC motor speed of a car. Suchmotor is broadly used in numerous applications like blowers, lathe machines, cranes, elevators,milling machines, fans, drilling rigs, etc. For achieving our aim, two optimization algorithms(Particle Swarm Optimization (PSO) and Bacterial Foraging Optimization (BFO)) will beexecuted to adjust the proposed controllers’ parameters. Accordingly, four Fractional-orderPID controllers (FoPID-controllers) will be formed in agreement with two types of schemes(Outstaloup’s and Continued Fraction Expansion (CFE) schemes), which will be used toapproximate the yielded Laplacian operators s±α, where 0 < α < 1.
Pollution detection for the singular linear parabolic equation
Iqbal M. Batiha,Imad Rezzoug,Taki-Eddine Oussaeif,Adel Ouannas,Iqbal H. Jebril 한국전산응용수학회 2023 Journal of applied mathematics & informatics Vol.41 No.3
In this work, we are concerned by the problem of identification of noisy terms which arise in singular problem as for remote sensing problems, and which are modeled by a linear singular parabolic equation. For the reason of missing some data that could be arisen when using the traditional sentinel method, the later will be changed by a new sentinel method for attaining the same purpose. Such new method is a particular least square-like method which permits one to distinguish between the missing terms and the pollution terms. In particular, a sentinel method will be given here in its more realistic setting for singular parabolic problems, where in this case, the observation and the control have their support in different open sets. The problem of finding a new sentinel is equivalent to finding singular optimality system of the least square control for the parabolic equation that we solve.
Deep-ultraviolet-light-driven reversible doping of WS2 field-effect transistors.
Iqbal, Muhammad Waqas,Iqbal, Muhammad Zahir,Khan, Muhammad Farooq,Shehzad, Muhammad Arslan,Seo, Yongho,Eom, Jonghwa RSC Pub 2015 Nanoscale Vol.7 No.2
<P>Improvement of the electrical and photoelectric characteristics is essential to achieve an advanced performance of field-effect transistors and optoelectronic devices. Here we have developed a doping technique to drastically improve electrical and photoelectric characteristics of single-layered, bi-layered and multi-layered WS2 field-effect transistors (FET). After illuminating with deep ultraviolet (DUV) light in a nitrogen environment, WS2 FET shows an enhanced charge carrier density, mobility and photocurrent response. The threshold voltage of WS2 FET shifted toward the negative gate voltage, and the positions of E and A1g peaks in Raman spectra shifted toward lower wavenumbers, indicating the n-type doping effect of the WS2 FET. The doping effect is reversible. The pristine characteristics of WS2 FET can be restored by DUV light illumination in an oxygen environment. The DUV-driven doping technique in a gas environment provides a very stable, effective, easily applicable way to enhance the performance of WS2 FET.</P>
Content-based Image Retrieval Using Haar Wavelet Transform and Color Moment
Iqbal Hasan Sarker,Shahed Iqbal 한국산학기술학회 2013 SmartCR Vol.3 No.3
Content-based image retrieval (CBIR) deals with the retrieval of most similar images corresponding to a query image from an image database by using visual contents of the image itself. It requires feature extraction and computation of similarity. In this paper, we propose a content-based image retrieval method that uses a combination of color and texture features. The Haar wavelet transform is used for texture feature extraction, and for color feature extraction we use color moments. The distance between the query image features and the database images’ features is computed by using Canberra distance. We assign weights to texture feature distance and color feature distance and calculate the similarity with combined feature distance. Experiment results reflect the importance of the Haar wavelet transform and color moments in the performance of our proposed CBIR method.