Hafeez Ullah

Enhanced ferromagnetic properties of Cu doped two-dimensional GaN monolayer

We demonstrate enhanced ferromagnetism in copper doped two-dimensionalGaNmonolayer (GaN-ML). Our first principle calculation based on density functional theory predicted that nonmagneticCu-dopant with concentration of 6.25% to be ferromagnetic (FM) in 2DGaNlayer which carries a magnetic moment of 2.0μBperCuatom and it is found to be long range magnetic coupling among theCu-dopant. The Cu-dopant in 2DGaN-ML which can be explained in terms ofp-dhybridization at Curie temperature and this dopant prefer the FM behavior in 2DGaNlayer. HenceCudoped 2DGaNlayer shows strong magnetic properties so that it is a promising material in the field of spintronics.

Classification of normal and abnormal brain MRI slices using Gabor texture and support vector machines

In computational and clinical environments, autoclassification of brain magnetic resonance image (MRI) slices as normal and abnormal is challenging. The purpose of this study is to investigate the computer vision and machine learning methods for classification of brain magnetic resonance (MR) slices. In routine health-care units, MR scanners are being used to generate a massive number of brain slices, underlying the anatomical details. Pathological assessment from this medical data is being carried out manually by the radiologists or neuro-oncologists. It is almost impossible to analyze each slice manually due to the large amount of data produced by MRI devices at each moment. Irrefutably, if an automated protocol performing this task is executed, not only the radiologist will be assisted, but a better pathological assessment process can also be expected. Numerous schemes have been reported to address the issue of autoclassification of brain MRI slices as normal and abnormal, but accuracy, robustness and optimization are still an open issue. The proposed method, using Gabor filter and support vector machines, classifies brain MRI slices as normal or abnormal. Accuracy, sensitivity, specificity and ROC-curve have been used as standard quantitative measures to evaluate the proposed algorithm. To the best of our knowledge, this is the first study in which experiments have been performed on Whole Brain Atlas-Harvard Medical School (HMS) dataset, achieving an accuracy of 97.5%, sensitivity of 99%, specificity of 92% and ROC-curve as 0.99. To test the robustness against medical traits based on ethnicity and to achieve optimization, a locally developed dataset has also been used for experiments and remarkable results with accuracy (96.5%), sensitivity (98%), specificity (92%) and ROC-curve (0.97) were achieved. Comparison with state-of-the-art methods proved the overall efficacy of the proposed method.

Molecular dynamics simulation of nanoscale surface diffusion of heterogeneous adatoms clusters

Molecular dynamics simulation employing the embedded atom method potential is utilized to investigate nanoscale surface diffusion mechanisms of binary heterogeneous adatoms clusters at 300 K, 500 K, and 700 K. Surface diffusion of heterogeneous adatoms clusters can be vital for the binary island growth on the surface and can be useful for the formation of alloy-based thin film surface through atomic exchange process. The results of the diffusion process show that at 300 K, the diffusion of small adatoms clusters shows hopping, sliding, and shear motion; whereas for large adatoms clusters (hexamer and above), the diffusion is negligible. At 500 K, small adatoms clusters, i.e., dimer, show almost all possible diffusion mechanisms including the atomic exchange process; however no such exchange is observed for adatoms clusters greater than dimer. At 700 K, the exchange mechanism dominates for all types of clusters, where Zr adatoms show maximum tendency and Ag adatoms show minimum or no tendency toward the exchange process. Separation and recombination of one or more adatoms are also observed at 500 K and 700 K. The Ag adatoms also occupy pop-up positions over the adatoms clusters for short intervals. At 700 K, the vacancies are also generated in the vicinity of the adatoms cluster, vacancy formation, filling, and shifting can be observed from the results.

ab intio study of points defects in 2D graphene layer

With a hexagonal (honeycomb) network of mono-layered carbon atoms, graphene has demonstrated outstanding electronic properties. This work describes the impact of deliberately introduced single, double and triple carbon vacancies in grapheme monolayer. In addition, these carbon vacancies were then substituted with gold atoms and their influence on the electronic properties of the two-dimensional (2D) graphene layers was investigated. In this regard, a first principle calculation was performed to examine electronic properties and formation energy of 2D graphene layer by applying density functional theory (DFT). Introduction of such defects appeared to increase the stability of the graphene sheet as confirmed by formation energy calculations. Moreover, decrease of formation energy was noticed to be significant with an increase in the number of defects. Band structure calculations described the shifting of localized states from valance to conduction bands which caused the transformation of semiconducting beha...

Hematological Complications and Rouleaux Formation of Blood Components (Leukocytes and Platelet Cells) and Parameters

This chapter has the detailed and depth knowledge about the hematological complications and Rouleaux formation of blood components (leukocytes and platelet cells) and parameters. The purpose of this chapter is to determine the changes in three parameters, i.e., cells count, shape of cells, and size of cells, prior and after addition of three analytes, i.e., sugar, sodium chloride, and pure water, for ten varying concentrations, i.e., from 0 to 450 mM, admixed in 2 ml blood for sugar [C6H12O6], 3 ml blood for sodium chloride [NaCl] and 4 ml blood for pure water. We have also discussed the effects of sugar, salt, and distilled water in comparison with the preexisting literature. This chapter also contains information’s about sample preparation; methodology of bright and dark field microscopy under transmission mode used for each blood cells and parameters, 2-D images of each phantom of each analyte for its normal sample and admixed sample, tables and graphs to express the variation in parameters relative to each phantom, results of each phantom and detailed discussions about changes in blood parameters and components mentioned above for each analyte.

Density Functional Theory (DFT) Study of Novel 2D and 3D Materials

In the present study, the analysis of novel 2D and 3D materials based on density functional theory (DFT) has been demonstrated which has drawn much research attention because of their fascinating properties. ZnO, GaN, diamond, and phosphorene are the best popular materials of recent study. Firstly, the enhancement of ferromagnetism in GaN monolayer doped with copper has been depicted. The findings of this study represent the ferromagnetic character due to the doping of 6.25% (concentration) of nonmagnetic Cu and magnetic long-range coupling among Cu dopant in GaN 2D monolayer which has the value of magnetic moment of 2.0 μB per Cu atom. While for ZnO (2D) layer, the formation of Schottky contact and the interfacial transfer of charge between Cu substrate and ZnO layer has been focused. In 3D materials case, diamond has been the center of attention because of its reliability in the materials society that is why different metals are doped in diamond. By the analysis of electronic properties, the semiconductor behavior is observed when diamond is doped with Ta. The negative value of formation energy makes oxygen-doped diamond layer, a thermodynamically favorable.

COMPARISON OF ELECTRONIC AND OPTICAL PROPERTIES OF GaN MONOLAYER AND BULK STRUCTURE: A FIRST PRINCIPLE STUDY

The semiconducting two-dimensional (2D) architectures materials have potential applications in electronics and optics. The design and search of new 2D materials have attracted extensive attention recently. In this study, first principle calculation has been done on 2D gallium nitride (GaN) monolayer with respect to its formation and binding energies. The electronic and optical properties are also investigated. It is found that the single isolated GaN sheet is forming mainly ionic GaN bonds despite a slightly weaker GaN interaction as compared with its bulk counterpart. The dielectric constant value of 2D GaN is smaller as compared to 3D GaN due to less effective electronic screening effect in the layer, which is accompanied by lesser optical adsorption range and suggested to be a promising candidate in electronic and optoelectronic devices.

Electronic properties of two-dimensional ZnO atomically sheet on Cu substrate: a first-principles study

Bulk ZnO has traditionally been regarded as multifunctional materials for energy and optoelectronics applications. Recently, exploring this material at the nanoscale has been reported and seeking a proper substrate is highly desired. In this work, the structural and electronic properties of graphene like ZnO two-dimensional (2D) monolayer are investigated by first principles calculation based on density functional theory. The alignment of the valence and conduction bands of ZnO with the state of Cu substrate is analyzed. Particularly the attention has been focused on the establishment of a Schottky contact and interfacial charge transfer between the 2D ZnO monolayer and Cu substrate. It is predicted that the electronic charges are accumulated on the Zn and O atoms due to d–d hybridization between Cu and Zn. Our study reveals that the significant interaction between the ZnO and Cu can greatly modify the electronic properties of the ZnO and suggests potential applications in nanoelectronic devices.