The scientific community believes that high-quality, bulk layered, semiconducting single crystals are crucial for producing two-dimensional (2D) nanosheets. This has a significant impact on current ...cutting-edge science in the development of next-generation electrical and optoelectronic devices. To meet this ever-increasing demand, efforts have been made to manufacture high-quality SnS2 single crystals utilizing low-cost CVT (chemical vapor transportation) technology, which allows for large-scale crystal production. Based on the chemical reaction that occurs throughout the CVT process, a viable mechanism for SnS2 growth is postulated in this paper. Optical, XRD with Le Bail fitting, TEM, and SEM are used to validate the quality, phase, gross structural/microstructural analyses, and morphology of SnS2 single crystals. Furthermore, Raman, TXRF, XPS, UV–Vis, and PL spectroscopy are used to corroborate the quality of the SnS2 single crystals, as well as the proposed energy level diagram for indirect transition in the bulk SnS2 single crystals. As a result, the suggested method provides a cost-effective method for growing high-quality SnS2 single crystals, which could lead to a new alternative resource for producing 2D SnS2 nanosheets, which are in great demand for designing next-generation optoelectronic and quantum devices.
As digital images are consistently generated and transmitted online, the unauthorized utilization of these images is an increasing concern that has a significant impact on both security and privacy ...issues; additionally, the representation of digital images requires a large amount of data. In recent years, an image compression scheme has been widely considered; such a scheme saves on hardware storage space and lowers both the transmission time and bandwidth demand for various potential applications. In this article, we review the various approaches taken to consider joint encryption and compression, assessing both their merits and their limitations. In addition to the survey, we also briefly introduce the most interesting and most often utilized applications of image encryption and evaluation metrics, providing an overview of the various kinds of image encryption schemes available. The contribution made by these approaches is then summarized and compared, offering a consideration of the different technical perspectives. Lastly, we highlight the recent challenges and some potential research directions that could fill the gaps in these domains for both researchers and developers.
Blockchain is a rapidly developing modern technology being used in various fields, including IoT-based healthcare, which is widely used nowadays because of its ability to increase the security, ...robustness, and reliability of distributed systems. Key features such as data immutability, decentralization, transparency, privacy, and distributed ledger are highly necessary to make blockchain an attractive technology. This paper gives a comprehensive survey of the application of IoT based blockchain technology. IoT and blockchain are required to enable real-time information processing and transaction implementation in an orderly manner. Digital data has become important for health services due to the hectic routine of daily life for patients and doctors. This study sheds light on the use of blockchain for IoT-based healthcare.
Electrical conductivity of Se90-xTe5Sn5Inx (x = 0, 3, 6 and 9) glassy systems was studied employing impedance spectroscopic technique in the frequency range 100 Hz to 1 MHz and in the temperature ...range 308-388 K. The DC conductivity (σdc) at each temperature was evaluated from the low frequency plateau region for all the samples under investigation. The bulk conductivity for each sample was also evaluated from Nyquist impedance plots. The semicircle shape of Nyquist plot exhibit dipolar nature of samples. The activation energy for glassy, amorphous and crystalline region from the Arrhenius plot of the DC conductivity and bulk conductivity was evaluated. From the results it is found that activation energy varied from 0.091 to 0.194 eV in glassy, 0.686 to 0.002 eV in amorphous and 0.215 to 0.503 eV in crystalline region. The activation energy (ΔE) from DC conductivity and bulk conductivity found to be close in corresponding regions. The pre-exponential factor was also calculated for all three regions.
•A facile, cheap, and one-step Solvothermal method adopted to synthesize Cr2O3 Nanocrystals (NCs).•TEM images of as-prepared Cr2O3 NCs depict highly monodispersity and uniformity of NCs.•A ...low-temperature antiferromagnetic interaction observed from ZFC/FC plot.•The nearest neighbour exchange coupling constant JNN has found to be −16 K.
Herein a one-step, easy, cheap and eco-friendly Solvothermal synthesis method has been used to synthesize monodisperse, uniform and ultrasmall chromium oxide (Cr2O3) nanocrystals (NCs). Transmission electron microscope (TEM) image of as-prepared Cr2O3 NCs shows the spherical shape with a uniform size of ∼4.5 nm. The oxidation state of chromium ion has confirmed by absorption as well as electron paramagnetic resonance (EPR) spectroscopy. Magnetic properties of as-synthesized NCs show low-temperature antiferromagnetic (AFM) exchange with Currie-Weiss (C-W) temperature ϴ = −160 K. Further, nearest neighbour exchange coupling constant JNN has found to be −16 K (Here K is Boltzmann constant) for Cr2O3 NCs by considering the nearest neighbours (Z) is 4.
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•Single source cluster approach used to synthesize Cu doped CdS (Cu:CdS) QDs.•Very high photoluminescence (PL) dopant emission observed in Cu:CdS QDs.•First-time femtosecond PL ...up-conversion technique used to study the hole dynamics of Cu:CdS QDs.•This simple system can boost the power conversion efficiency of solar cell device.
Herein, femtosecond photoluminescence up-conversion (u-PL) spectroscopy has been carried out to elucidate charge carrier relaxation dynamics of the hole in 2 nm copper doped CdS (Cu:CdS) QDs. The hole capturing time at the Cu defect state from the valance band edge of the CdS host appeared significantly faster (437 fs) compared to pure CdS QDs (670 fs). This faster hole capturing in Cu:CdS QDs can compete with Auger-type cooling, and consequently, we can expect slower electron cooling in this system.
Unlike traditional encryption methods, Generative Adversarial Network (GAN)-based methods possess a high level of security for digital images. Many existing simple encryption methods may be less ...secure than expected and have high storage costs. This paper proposes a GAN-based encryption method to secure digital images, solving these problems. First, a random sequence generator using a GAN with cross-coupled logistics and a Henon map is generated to encrypt an image. Next, the encrypted image is downsampled into one-fourth of the original size and sent to the receiver. Finally, image reconstruction uses a Customized Super Resolution Network (CSRNet) rather than decompressing the image at the receiver side. Our extensive experimental results demonstrate that the proposed method achieves NPCR, UACI, entropy, PSNR and SSIM up to 0.99604, 0.33460, 7.9993, 37.0462 dB and 0.94561, respectively. Further, our encryption method achieves up to 75% faster than the recent methods when evaluated on two standard datasets. Therefore, the proposed GAN-Based solution can possess a high level of security and save sufficient storage space for any practical application.
Medical images contain significant patient information, and this confidential data should not be accessed without proper authorisation. Concurrently, due to the high redundancy of image data, ...compression is necessary to minimise image size and efficiently utilise network resources. This paper presents an effective joint encryption and compression method for medical images that prevent critical data leakage while reducing redundancy. Initially, a powerful real-time object detection method, You Only Look Once v7, is employed to accurately and swiftly detect the region of interest (ROI) within the medical images. Subsequently, a joint three-dimensional chaotic map and Huffman encoding are applied to secure medical images without compromising the compression ratio or increasing the time cost. Lastly, a super-resolution network is established at the receiver end to better reconstruct the ROI image for precise diagnostic purposes. The comprehensive experimental analysis demonstrates that our method delivers high levels of security, compression, and visual quality performance on standard datasets used in smart healthcare applications, at a minimum. Furthermore, our approach outperforms other competitive state-of-the-art schemes when compared. We hope this study will inspire further research within the healthcare community.
•A joint encryption–compression based method for medical images is proposed.•YOLOv7 is used to detect ROI in medical images with high accuracy and speed.•A reconstruction network is utilized to recover the ROI at receiver side.•Our method outperforms other competitive schemes when compared.
Glass transition kinetics of glassy Se₉₀₋ₓTe₅Sn₅Inₓ (x=0, 3, 6 and 9) alloys have been investigated using differential scanning calorimetric (DSC) technique under non-isothermal conditions at ...different heating rates 5, 10, 15 and 20K/min. It is observed that in these glasses, the glass transition temperature (Tg) is found to be dependent on composition and heating rates. The activation energy of glass transition (Eg), fragility index (F) and stability parameter (S) are evaluated for glassy Se–Te–Sn–In alloys. The glass transition activation energy (Eg) and fragility index (F) were found to be minimum at 9at.% of In, as well as thermal stability parameter (S) was found to be maximum at same glassy composition due to maximum crosslinking structures. Results indicate that thermal stability increases on the addition of In to ternary Se₉₀Te₅Sn₅ glass. Hence Se₈₁Te₅Sn₅In₉ glass is the better thermally stable glass in this system.
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