Plasmonics, often referred as “light on wire”, is an emerging nano-scale technology having the advantages of higher speed computing over the electronic devices and comparatively smaller size than the ...electro optical devices. With the help of plasmonics, it is possible to transmit data between chips at optical speeds and thus opening the doors towards miniaturization of devices and faster computers. Reflective codes are the self-complementing codes, which are used for communicating with computers. In this work, a novel design of plasmonic 2421 reflective code using plasmonic Mach–Zehnder interferometer has been proposed. As the designed reflective code is plasmonics based, hence it has smaller size, better processing speed, faster switching of light, better optical stability, lesser power consumption than the existing designs of codes. The footprint of the proposed device is only 190 µm × 35 µm with an extinction ratio of 18.23 dB. The performance of the device is theoretically analysed using a numerical analysis technique i.e. finite-difference-time-domain (FDTD) method and then comparing the simulation results of FDTD method with the MATLAB simulation results.
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•Nanomaterials possess exceptional optoelectric and electromagnetic properties due to their small size and large surface area•Nanomaterials have been extensively utilized in the ...biomedical and bioengineering fields, ranging from diagnostics to therapeutics.•Surface modifications of nanomaterials are essential to enhance their adsorbing capability for biomarkers on the nanomaterial surface.•The study explores surface modifications of diverse nanomaterials, encompassing metallic nanoparticles, carbon-based nanomaterials, and self-assembled materials.•The emphasis of the paper is on different surface modification techniques to improve the functionality and applicability of nanomaterials in medical diagnosis.
Ranging from diagnostics to therapeutics, nanomaterials have been widely exploited in the fields of biomedicine and bioengineering. The past few decades have witnessed the development of a number of nanomaterials for bringing out the best results in the field of medical diagnosis. However, despite possessing extremely unique material properties, many of them lack surface heterogenic reactivity, which is a crucial factor for the specific binding of biomarkers on the nanomaterial surface. For this reason, nanomaterials have to undergo surface modifications so as to increase the adsorbing capability of biomarkers over the functionalized nanomaterial surface. Keeping in mind the importance of surface modification for successful application of nanomaterials in medical diagnosis, different surface modifications of a number of nanomaterials like metallic nanoparticles (metal and metal oxide nanoparticles, binary compounds), carbon-based nanomaterials (graphene-based nanomaterials, carbon dots, carbon nanotubes), and self-assembled materials have been discussed in this paper. Different types of interactions, such as covalent and non-covalent forces such as electrostatic force, hydrogen bonds, and Vander Waals, have been reported in the literature, which lead to the functionalization of nanoparticles. It has been found that organic molecules such as phosphates, citrates, thiols, amines, and various polymer molecules such as dextran, chitosan, PEG, etc. and inorganic compounds such as metallic elements and ligands are significant in the surface functionalization process of freshly synthesized nanoparticles. The self-assembly of nanostructures has also been found to be beneficial in terms of compatibility in biological media and to be a promising technique for biosensing-related applications of these nanostructures. This study aims at throwing light on the technology prevalent in the field of making nanostructures more advantageous in the field of biosensing by functionalizing their surface, and it indicates that by collaborating nanotechnology with different disciplines such as chemistry, biology, physics, and medicine, it will emerge as the most preferred and commercialized platform for biomedical functions such as biosensing, bioengineering, gene therapy, drug delivery, etc.
A comparative study on the influence of different 3d transition metal ions (Cr3+, Fe3+ and Ni2+) on the structural, dielectric, ferroelectric and electrocaloric response of BST ceramics is reported ...in the present work. Conventional solid-state reaction method was adopted for preparing the samples. A pure perovskite phase with tetragonal structure was confirmed by X-ray diffraction (XRD) analysis. Tetragonality was found to be decreased with the substitution of transition metal ions except in Cr3+ substituted sample. The dielectric behavior was investigated as a function of temperature (30 °C–150 °C) at different frequencies. Dielectric constant (ε) data was fitted with Power Law above Tc and diffused phase behavior was observed in the samples. P-E loops were recorded at different applied electric fields and temperatures. Improvement in ferroelectric properties (Pr = 10.56 μC/cm2, Ec = 2.40 kV/cm and Pr/Pmax = 0.53) was observed for Cr-substituted sample. Indirect method based on Maxwell's entropy-polarization relationship was employed to evaluate the electrocaloric effect (ECE) for all the samples. The value of ΔTmax was found to be maximum for (1.113K) for Cr substituted samples. The results show that Cr substituted BST are suitable for use in capacitor, memory devices and new generation solid-state cooling devices.
We investigate the dynamics of quantum speed limit time under the effect of Markovian and non-Markovian dynamics. Memory effect plays a fundamental role in the dynamics of open quantum system. In the ...first case quantum channel has memory there exist correlations between sucessive uses of channels. Such type of channel called correalted channel.We study quantum speed limit time for Markovian and non-Markovian dynamics. We discuss measure of QSL, how correlations affect the rate of quantum speed limit. In this work find one connection between non-Markovianty and quantum speed limit. We show that the non Markovian evolution can speed up quantum evolution, therefore lead to smaller quantum speed limit time. We establish connection between information loss, quantum speed limit time that might be helpful for further investigation in quantum processing theoretical task.
This article summarizes the application of various optical techniques for biological sensing. The presence of abnormal quantities of biomolecules (such as glucose, haemoglobin, etc.) or pathogens ...(such as viruses or bacteria in body cells) can be used to diagnose any ailment or malfunction of any part of the body. Additionally, the concentration of biomolecules such as glucose and haemoglobin in blood serves as an indicator of the body's normalcy. Thus, the ability to detect abnormalities in blood or human cells more easily and rapidly can be a boon to society. Optical techniques are one such approach for developing biosensors. The extremely sensitive, label-free, real-time dynamic monitoring capabilities of optical techniques-based sensors have piqued the interest of a large number of researchers. In this paper, we have reviewed the present advancements in the field of prism based SPR biosensors i.e., the Kretschmann SPR (K-SPR) configuration-based biosensors for sensing vital biomolecules in human body like glucose and haemoglobin and microorganism like Pseudomonas bacteria.
A comparative study is reported on the ferroelectric ceramics with compostional formula Ba0·98La0·02Ti0·98Fe0·02O3 (BLTF1) and Ba0·97La0·02Ti0·98Fe0·02O3 (BLTF2; valency compensated). The samples ...were prepared by solid state route and sintered in air at 1325 °C for 4 h. The X-ray diffraction analysis confirmed the formation of tetragonal perovskite phase. The prepared samples were characterized for their dielectric and ferroelectric properties at different temperatures at 1, 5, 10 and 100 kHz. Enhancement in ferroelectric properties (Pr = 11.25 μC/cm2, Ec = 9.05 kV/cm) was observed in BLTF2 ceramics as compared to BLTF1 ceramics (Pr = 6.53 μC/cm2, Ec = 9.35 kV/cm) along with the observation of electrocaloric effect. The value of piezoelectric coefficient ‘d33’ was found to be 140 pC/N and 163 pC/N for BLTF1 and BLTF2 samples respectively. The present investigations show that the valency compensation method can improve the ferroelectric properties of the ferroelectric ceramics thereby making them more suitable for different applications.
The current study demonstrates the effect of Ni-substitution on the structural, dielectric and ferroelectric properties of Ba
0.90
Sr
0.10
Ti
1-x
Ni
x
O
3
(where x = 0.000, 0.005, 0.015 and 0.025) ...ceramics, synthesized by solid-state reaction approach. A pure perovskite phase with tetragonal structure has been confirmed by X-ray diffraction (XRD) analysis. Scanning electron microscope (SEM) images revealed change in microstructure. The dielectric behavior of the prepared ceramics was investigated as a function of temperature (30-150°C) at different frequencies. The results indicate that there is an increase in dielectric constant (ϵ
RT
) and low dielectric loss (tanδ
RT
) were obtained at room temperature by substitution of Ni
2+
ions in BST ceramics, offering a promising material for capacitor applications at room temperature. Room temperature P-E loops were recorded at different applied electric fields and typical hysteresis loops were obtained. Improvement in the values of P
r
and P
max
was observed by substitution of Ni
2+
ions.
In this context, formamide is explored as an efficient solvent for the dispersion of GO sheets and preparation of graphene oxide lyotropic liquid crystals (GOLLCs). Polarizing optical microscopy ...(POM) studies confirm that GO/formamide dispersion shows smectic phase at lower concentration (< 2 mg/mL) and nematic phase up to 300 mg/mL. GOLLCs are found stable for up to 24 months. Probably it is the first report on the formation of GOLLCs in formamide and their long-term stability up to 24 months. GOLLCs are studied for steady and dynamic rheological behavior at room temperature. All the GOLLCs exhibit shear-thinning fluid behavior under the shear rate 1–100 s−1. Dynamic rheology reveals that GOLLCs follow solid viscoelastic behavior till 20 mg/mL concentration and then depict long range viscoelastic behavior at higher concentrations. Complex moduli behavior of GOLLCs has been studied to predict their elasticity. The scaling analysis of tunable viscoelastic GOLLCs is computed from Er=Ax−xc4.43. The free-standing film is prepared via thermal treatment method from 2 mg/mL GOLLCs and studied for structural and photocatalytic degradation behavior. rGO film shows 99.18% and 97.87% degradation efficiency for malachite green and methyl orange organic dyes respectively under UV light and is found stable up to 3 cycles.
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•Highly stable formamide/GO based GOLLCs are prepared considering intermolecular interactions.•Smectic and nematic LLCs phases are observed as a function of increasing GO concentration.•Shear and dynamic rheological behavior are correlated with the structural parameters considering the domain size concept.•Shear thinning, viscoelastic and long-range viscoelastic behavior of GOLLCs.•rGO film from GOLLCs has been developed and tested for photodegradation of organic dyes.
In this study, we investigated the impact of Chromium substitution on the structural, dielectric and ferroelectric characteristics of Ba0·90Sr0·10Ti1-3x/4CrxO3 (x = 0, 0.005, 0.010, 0.015 and 0.020) ...ceramics fabricated by solid state reaction method. Rietveld refinement of X-ray diffraction pattern confirmed tetragonal perovskite structure for all the samples. Based on the crystal structure and the lattice parameter obtained through XRD measurement, the Madelung energy of each sample was computed. SEM images revealed a reduction in grain size with rising Cr concentration. TEM, HRTEM, SAED and EDS analysis was carried out for BST-Cr3 sample. Diffused rings observed in Selective Area Electron Diffraction (SAED) patterns indicate the crystallinity of the sample. EDS analysis indicated the presence of Ba, Sr, Ti, O and Cr elements. In the temperature range of 30 °C–150 °C, dielectric measurements (dielectric constant ‘ε’ and tangent loss ‘tanδ’) have been made at different frequencies (1, 10, 50, 100 and 1000 kHz). The samples displayed a diffused phase transition, with noticeable reduction in Curie temperature ‘Tc’ and tangent loss ‘tanδ’ with the substitution of Cr. Polarization versus electric field loops were recorded at different electric fields (5, 10, 15, 20 and 25 kV/cm) and improved values of remnant polarization ‘Pr’ and coercive field ‘Ec’ were observed. A lower Ec value facilitates easier domain movement within the unit cell, leading to enhanced ferroelectric properties. Temperature dependent P-E loops indicated that as the temperature increased, the material became softer accompanied by simultaneous reduction in Pr and Ec values.
Scheme for the formation of lamellar smectic phases in GO/Glycerol dispersion.
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•Reporting first time the dispersion of GO in glycerol which is stable up to 120 days.•Formation of ...lamellar smectic structures with surface chirality.•In-situ reduction of GO to rGO during sonication within 1 h.•Higher viscosity of GOLLC systems and their viscoelastic behaviour.•G′/G′′ ratio lie between 1 and 2.4 which enable the spray coating and ink jet printing applications of studied GOLLC systems.
Herein, we report the dispersion and stabilization of graphene oxide (GO) in the polar organic solvent glycerol (C3H8O3). The GO/glycerol (0.5 mg/mL and 1 mg/mL) dispersions are found stable for about 4 months. Strong hydrogen bonding and electrostatic repulsive interactions amid solvent and solute may be responsible for the stable dispersion. Moreover, such interactions and the non-covalent bonding may also lead to the organization of GO sheets in the self-sustained anisotropic supramolecular lyotropic structures in glycerol. Two dimensional lamellar smectic lyotropic phases with surface chirality have been observed for 0.5 mg/mL and 1 mg/mL, GO/glycerol dispersions. Partial reduction of GO into rGO has been observed and confirmed by UV–Visible measurement. Graphene-based lyotropic structures exhibit ionic conductivity of micron order (S/cm) and also possesses conduction activation energy of range 13–14 kJ/mol. GO/glycerol-based Lyotropic dispersions show non-Newtonian behaviour along with the decrease in the viscosity as the GO concentration is increased. The maximum viscosity noted for these systems is ~630 mPa.s. Viscoelastic behaviour of lyotropic dispersion has been confirmed by dynamic rheology and G'/G'' G'(storage) and G'' (loss) modulus crossover. Rheological studies infer that such lyotropic dispersion with high viscosity can be explored for ink-jet printing and printing of flexible membrane.
