Ghulam Ishaq Khan Institute of Engineering Sciences and Technology

About: Ghulam Ishaq Khan Institute of Engineering Sciences and Technology is a education organization based out in Topi, Pakistan. It is known for research contribution in the topics: Thin film & Quantum efficiency. The organization has 618 authors who have published 940 publications receiving 10674 citations.

New directions in hypernuclear physics

Abstract: A hypernucleus, a subatomic bound system with at least one hyperon, is a great test ground to investigate nuclear forces and general baryonic interactions with up, down and strange quarks. Hypernuclei have been extensively studied for almost seven decades in reactions involving cosmic rays and with accelerator beams. In recent years, experimental studies of hypernuclei have entered a new stage using energetic collisions of heavy-ion beams. However, these investigations have revealed two puzzling results related to the lightest three-body hypernuclear system, the so-called hypertriton, and the unexpected existence of a bound state of two neutrons with a Λ hyperon. Solving these puzzles will not only impact our understanding of the fundamental baryonic interactions with strange quarks but also of the nature of the deep interior of neutron stars. In this Perspective, we discuss approaches to solving these puzzles, including experiments with heavy-ion beams and the analysis of nuclear emulsions using state-of-the-art technologies. We summarize ongoing projects and experiments at various facilities worldwide and outline future perspectives. The study of hypernuclei contributes to the understanding of the fundamental baryonic interactions and the physics of neutron stars. This Perspective discusses different experimental approaches to answer open questions regarding hypernuclei.

Reversible watermarking method based on adaptive thresholding and companding technique

Abstract: Embedding and extraction of secret information as well as the restoration of the original un-watermarked image are highly desirable in sensitive applications such as military, medical, and law enforcement imaging. This paper presents a novel reversible watermarking approach for digital images using integer-to-integer wavelet transform, companding technique, and adaptive thresholding, enabling it to embed and recover the secret information as well as restore the image to its pristine state. The proposed method takes advantage of block-based watermarking and iterative optimization of threshold for companding which avoids histogram pre-and postprocessing. Consequently, it reduces the associated overhead usually required in most of the reversible watermarking techniques. As a result, it generates less distortion between the watermarked and the original image. Experimental results on regular as well as medical images show that the proposed method outperforms the existing reversible watermarking approaches reported in the literature.

A facile route to a high-quality graphene/MoS2 vertical field-effect transistor with gate-modulated photocurrent response

Abstract: Two-dimensional layered materials, such as graphene (Gr) and molybdenum disulfide (MoS2), have become fascinating and exciting candidates for next-generation electronic device materials. Their vertical combinations have led to novel electronic and photonic devices. We fabricated vertical field-effect transistors (FETs) with h-BN/Gr/MoS2/Mo multi-heterostructures. A facile route was followed to design high-quality vertical FETs with improved performance. MoS2 was directly transferred to SiO2/h-BN/Gr without using any polymer, which produced a clean interface between Gr and MoS2. A high current ON–OFF ratio of ∼106 was demonstrated with a high current density of ∼105 A cm−2. Our results were attributed to the high-quality bottom Gr on h-BN, the top-most molybdenum metal contact, and the clean interface between Gr and MoS2. The photoresponse of vertical FETs was also investigated under deep ultraviolet irradiation. The current density and photocurrent response of these vertical devices were strongly dependent on the back-gate voltage.