The crystallization kinetics of bulk Se
90−
x
Te
5Sn
5In
x
(
x=0, 3, 6 and 9) multi-component chalcogenide glasses have been studied using differential scanning calorimetry (DSC) with heating rates ...5, 10, 15 and 20
K/min under non-isothermal conditions. Values of various kinetic parameters of crystallization, such as onset crystallization temperature (
T
c
), peak crystallization temperature (
T
p
), activation energy of crystallization (
E
c
), rate constant (
K
p
), Hruby number (
K
gl
) and the order parameter (
n) have been determined. It was found that activation energy of crystallization and rate constant (
K
p
) are minimum at 9
at% In. On the basis of the obtained experimental data the temperature difference (
T
c
−T
g
) and
K
gl
increase with In concentration, which further indicates that 9
at% In glass is most thermally stable in the entire composition range of investigation.
The calorimetric parameters of glassy Se.sub.98-xCd.sub.2In.sub.x (x = 0, 2, 6 and 10) alloys were investigated using differential scanning calorimetry (DSC) under non-isothermal conditions at ...different heating rates of 5, 10, 15 and 20 K min.sup.-1. The composition dependencies of activation energy of glass transitions (E.sub.g), crystallization activation energy (E.sub.c), fragility index (F), Hruby number (K.sub.gl) and rate constant (K.sub.p) were evaluated from DSC curves. Results indicate that kinetic parameter varies with In content in Cd-Se glassy matrix. It is observed that crystallization activation energy (E.sub.c) and K.sub.p are minimum and K.sub.gl is maximum for Se.sub.92Cd.sub.2In.sub.6 glass. Therefore, Se.sub.92Cd.sub.2In.sub.6 glass is the most thermally stable glass and has highest glass-forming ability in this series. It can be explained by chemical bond theory of solids.
The calorimetric parameters of glassy Se sub(98-x)Cd sub(2)In sub(x) (x = 0, 2, 6 and 10) alloys were investigated using differential scanning calorimetry (DSC) under non-isothermal conditions at ...different heating rates of 5, 10, 15 and 20 K min super(-1). The composition dependencies of activation energy of glass transitions (E sub(g)), crystallization activation energy (E sub(c)), fragility index (F), Hruby number (K sub(gl)) and rate constant (K sub(p)) were evaluated from DSC curves. Results indicate that kinetic parameter varies with In content in Cd-Se glassy matrix. It is observed that crystallization activation energy (E sub(c)) and K sub(p) are minimum and K sub(gl) is maximum for Se sub(92)Cd sub(2)In sub(6) glass. Therefore, Se sub(92)Cd sub(2)In sub(6) glass is the most thermally stable glass and has highest glass-forming ability in this series. It can be explained by chemical bond theory of solids.
In the category of 2D materials, MoS
a transition metal dichalcogenide, is a novel and intriguing class of materials with interesting physicochemical properties, explored in applications ranging from ...cutting-edge optoelectronic to the frontiers of biomedical and biotechnology. MoS
nanostructures an alternative to heavy toxic metals exhibit biocompatibility, low toxicity and high stability, and high binding affinity to biomolecules. MoS
nanostructures provide a lot of opportunities for the advancement of novel biosensing, nanodrug delivery system, electrochemical detection, bioimaging, and photothermal therapy. Much efforts have been made in recent years to improve their physiochemical properties by developing a better synthesis approach, surface functionalization, and biocompatibility for their safe use in the advancement of biomedical applications. The understanding of parameters involved during the development of nanostructures for their safe utilization in biomedical applications has been discussed. Computational studies are included in this article to understand better the properties of MoS
and the mechanism involved in their interaction with biomolecules. As a result, we anticipate that this combined experimental and computational studies of MoS
will inspire the development of nanostructures with smart drug delivery systems, and add value to the understanding of two-dimensional smart nano-carriers.
Enhanced electrocaloric response in lead‐free 0.8Na
0.5
Bi
0.5
TiO
3
‐0.2SrTiO
3
(NBT‐0.2ST) ceramics are investigated using an indirect approach based on Maxwell's relations over a wide operating ...temperature range. The electrocaloric effect (ECE) is obtained over a broad temperature range with the maximum temperature change (
T
) value reaching 0.75 K at the working temperature of 400 K under the electric field of 35 kV cm
−1
. The maximum EC coefficient () is found to be 0.022 K·cm kV
−1
at 400 K. Energy storage density of NBT‐0.2ST are calculated and found to be 0.36 J cm
−3
at 393 K. High value of ECE and a wide working temperature range (350–450 K) make it a promising lead‐free ferroelectric material for applications in cooling technologies.
Manipulation of carrier spins in semiconductors for spintronics applications has received great attention driven by improved functionalities and higher speed operation. Doping of semiconductor ...nanocrystals by transition-metal ions pronounced as diluted magnetic semiconductors (DMS) has attracted tremendous attention. Such doping is, however, difficult to achieve in low-dimensional strongly quantum-confined nanostructures by conventional growth procedures. In the present case, magic-sized, pure, and Cr-doped CdS DM-QDs have been synthesized by solution phase chemistry (lyothermal method). Structural, optical, and magnetic investigation suggest an intrinsic nature of ferromagnetism with highly quantum-confined system. Optical and magnetic results of pure and doped QDs reveal major physical consequences of dopant localization within the capacity to engineer dopant-carrier exchange interactions introducing magnetic functionalities within the host semiconductor lattice. Unpaired Cr ions in Cd substitutional sites could create spin ordering and ferromagnetic coupling. The results presented herein illustrate some of the remarkable and unexpected complexities that can arise in doped QDs.
Recently, significant attention has been focused on copyright protection of medical images, causing watermarking to become a prevalent research topic. In this paper, we propose an optimisation-based ...robust watermarking algorithm for the copyright protection of colour medical images. Initially, we decompose a host medical image by lifting wavelet transform (LWT), followed by discrete cosine transform (DCT) into transformed coefficients, and then embed multiple watermarks into the transformed host image by using hybrid optimisation algorithms. To further improve security and reduce the channel noise distortion, we then apply hashing and Hamming code to image and text mark, respectively, before the embedding process. Finally, we utilise 2D chaotic map to encrypt the marked media, aiming to achieve enhanced security and confidentiality. The experimental outcome shows satisfactory invisibility, watermark payload and robustness against image-processing attacks. Furthermore, through numerous comparative experiments with nine state-of-the-art algorithms on two standard datasets, the effectiveness of the proposed algorithm is demonstrated.
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•An optimisation-based robust watermarking algorithm for colour medical images.•Combination of LWT-DCT is used to embed dual watermarks for better robustness and security.•Hashing and hamming code are employed for additional security and robustness of the image and text mark, respectively.•Various experiments are performed to verify the effectiveness of the algorithm.
Herein, we report temperature- and field-induced magnetic states in CsPbBr3 perovskite quantum dots (PQDs) attributed to Br defects. We find that temperature-dependent structural distortion is the ...main source of various temperature-induced magnetic states in Br-defect host CsPbBr3 PQDs. Comprehensively examined magnetization data through Arrott plots, Langevin and Brillouin function fitting, and structural analysis reveal the presence of various oxidation states (i.e., Pb0, Pb+, Pb2+, and Pb3+) yielding different magnetic states, such as diamagnetic states above 90 K, paramagnetic states below ≈90 K, and perhaps locally ordered states between 58 and 90 K. It is realized from theoretical fits that paramagnetic ions exist (i.e., superparamagnetic behavior) due to Br defects causing Pb+ (and/or Pb3+ ions) in the diamagnetic region. We anticipate that our findings will spur future research of the development of spin-optoelectronics, such as spin light-emitting diodes, and spintronics devices based on CsPbBr3 PQDs.
