Effect of Annealing Temperature on the Structural and Optical Properties of ZrO2 Thin Films

Davinder Kumar,Avtar Singh,Navneet Kaur,Apoorva Katoch,Raminder Kaur 한국재료학회 2022 한국재료학회지 Vol.32 No.5

Transparent thin films of pure and nickel-doped ZrO2 are grown successfully by sol-gel dip-coating technique. The structural and optical properties according to the different annealing temperatures (300 oC, 400 oC and 500 oC) are investigated. Analysis of crystallographic properties through X-ray diffraction pattern reveals an increase in crystallite size due to increase in crystallinity with temperature. All fabricated thin films are highly-oriented along (101) planes, which enhances the increase in nickel doping. Scanning electron microscopy and energy dispersive spectroscopy are employed to confirm the homogeneity in surface morphology as well as the doping configuration of films. The extinction coefficient is found to be on the order of 102, showing the surface smoothness of deposited thin films. UV-visible spectroscopy reveals a decrease in the optical band gap with the increase in annealing temperature due to the increase in crystallite size. The variation in Urbach energy and defect density with doping and the change in annealing temperature are also studied.

Computationally efficient variational Bayesian method for PAPR reduction in multiuser MIMO‐OFDM systems

Davinder Singh,Rakesh Kumar Sarin 한국전자통신연구원 2019 ETRI Journal Vol.41 No.3

This paper investigates the use of the inverse‐free sparse Bayesian learning (SBL) approach for peak‐to‐average power ratio (PAPR) reduction in orthogonal frequency‐division multiplexing (OFDM)‐based multiuser massive multiple‐input multiple‐output (MIMO) systems. The Bayesian inference method employs a truncated Gaussian mixture prior for the sought‐after low‐PAPR signal. To learn the prior signal, associated hyperparameters and underlying statistical parameters, we use the variational expectation‐maximization (EM) iterative algorithm. The matrix inversion involved in the expectation step (E‐step) is averted by invoking a relaxed evidence lower bound (relaxed‐ELBO). The resulting inverse‐free SBL algorithm has a much lower complexity than the standard SBL algorithm. Numerical experiments confirm the substantial improvement over existing methods in terms of PAPR reduction for different MIMO configurations.

A HYBRID ALGORITHM FOR LUNG CANCER CLASSIFICATION USING SVM AND NEURAL NETWORKS

Pankaj Nanglia,Sumit Kumar,Aparna N. Mahajan,Paramjit Singh,Davinder Rathee 한국통신학회 2021 ICT Express Vol.7 No.3

The present research article focused on the factual findings of the potential usage of the combinational Feed-Forward Back Propagation Neural Network as a judgment making for lung cancer. In this context, Support Vector Machine is integrated with Feed-Forward Back Propagation Neural Network to create a hybrid algorithm that further helps in reducing the computation complexity of the classification. A set of 500 images are utilized in which 75% data is used for the training purpose and the rest 25% is used to achieve the classification. In the view of forgoing, a three-block mechanism is proposed for the classification in which the first block preprocesses the dataset, the second block extracts the features via the SURF technique followed by the optimization using Genetic Algorithm and the terminal block is for the classification via FFBPNN. The hybrid classification algorithm is named as Kernel Attribute Selected Classifier and the overall classification accuracy of the proposed algorithm is 98.08%. Herein, the objective of the study is to enhance the classification accuracy by applying a hybrid classification algorithm.

Enhanced exchange bias in magnetron-sputtered NieMneSbeAl ferromagnetic shape memory alloy thin films

Rahul Barman,Sushil Kumar Singh,Davinder Kaur 한국물리학회 2014 Current Applied Physics Vol.14 No.12

In the present study, the influence of aluminium (Al) addition on the martensite-austenite phase transformation and exchange bias of NieMneSb films have been investigated. NieMneSbeAl films with different Al concentration (~0e5.6%) were deposited by co-sputtering of NieMneSb and Al targets. Experimental results revealed the decrease in martensitic transformation temperature with increasing Al content upto a certain extent (3.3%) beyond which martensitic transformation was suppressed. Paramagnetic to ferromagnetic transition temperature (TC) also decreased with increasing Al concentration. Ni50Mn36.3Sb10.4Al3.3 thin film showed significant improvement in exchange bias field as compared to pure Ni50.3Mn36.9Sb12.8 thin film. This enhancement in the exchange bias field HEB ¼ 611 Oe at 10 K is attributed to the increase of AFM-FM interactions that result from the decrease of MneMn distance due to the incorporation of Al atoms. This behaviour is an additional property of the FSMA thin films apart from various other multifunctional properties and therefore, is of technological importance for their applications in magnetic storage devices. ©

Exemestane encapsulated copolymers L121/F127/GL44 based mixed micelles: solubility enhancement and in vitro cytotoxicity evaluation using MCF-7 breast cancer cells

Singh Gurdeep,Singh Davinder,Choudhari Manisha,Kaur Simran Deep,Dubey Sunil Kumar,Arora Saroj,Bedi Neena 한국약제학회 2021 Journal of Pharmaceutical Investigation Vol.51 No.6

Purpose The present study aimed to develop a novel therapeutic approach for controlled delivery of exemestane (EXE) to cancer cells using nanostructured polymeric micelles. Methods A simplex centroid design of experiment study was employed for optimizing the polymeric micelle formulation to achieve the desired critical quality attributes, including micelle size, drug loading (DL), encapsulation efficiency (EE), and critical micelle concentration (CMC). The oil-in-water (o/w) solvent evaporation method was used to prepare mixed micelles (MMs) of copolymers L121/F127/GL44 for encapsulating EXE. Profile analysis tensiometer methods were used to determine the CMC of the copolymer mixture. EXE-MMs, blank mixed micelles, and lyophilized mixed micelles (Lyp- EXE-MMs) were characterized for other key quality attributes, such as zeta potential, chemical interactions, and morphology. Results The optimized ratio of L121/F127/GL44 was 1.98, 0.812, and 1.20, respectively, providing EXE-MMs with small micelle sizes (35.45 ± 1.20 nm), higher EE (89.75 ± 2.14%), and DL (5.85 ± 2.14%). EXE-encapsulated MMs exhibited an in vitro sustained release profile with improved cytotoxicity against MCF-7 cells than that with pure EXE. The cellular growth inhibitory concentration ( IC50) of EXE-MMs was 0.225 ± 0.124 μg/ml, while that of naïve EXE was 7.58 ± 0.145 μg/ ml. Moreover, in vivo pharmacokinetic parameters of EXE micellar formulation showed significant improvement in Cmax and AUC (0–72 h), viz. 207.54 ± 18.65 ng/ml and 3530.77 ± 212.25 ng h/ml, respectively, suggesting enhanced bioavailability than that of pure EXE. Conclusion EXE-MMs have a great potential for enhancing the bioavailability of EXE.

Improved resistive switching performance in Cu-cation migrated MoS2 based ReRAM device incorporated with tungsten nitride bottom electrode

Ravi Prakash,Shubham Sharma,Anuj Kumar,Davinder Kaur 한국물리학회 2019 Current Applied Physics Vol.19 No.3

The resistive switching characteristics of sputtered deposited molybdenum disulphide (MoS2) thin film has been investigated in Cu/MoS2/W2N stack configuration for Resistive Random Access Memory (ReRAM) application. The benefits of incorporating tungsten nitride (W2N) as a bottom electrode material were demonstrate by stability in operating voltages, good endurance (103 cycles) and long non-volatile retention (103 s) characteristics. Resistive switching properties in Cu/MoS2/W2N structure are induced by the formation/disruption of Cu conducting filaments in MoS2 thin film. Ohmic law and space charge limited current (SCLC) are observed as dominant conduction mechanism in low resistance state (LRS) and high resistance state (HRS) respectively. This study suggests the application of MoS2 thin films with W2N bottom electrode for next generation non-volatile ReRAM application.

Fabrication of Densely Distributed Silver Indium Selenide Nanorods by Using Ag+ Ion Irradiation

Dinesh Pathak,R. K. Bedi,Davinder Kaur,Ravi Kumar 한국물리학회 2010 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.57 No.3

We prepared polycrystalline silver indium selenide thin films by vacuum evaporation on Si (100) substrates at a high temperature using a stochiometric powder. The films were characterized by X-ray diffraction (XRD) and UV-VIS-NIR spectroscopy. For the fabrication of densely distributed one-dimensional nanostructures of silver indium selenide on Si substrates, thermally evaporated films of AIS on Si (100) substrates were irradiated by incident 200-MeV Ag+ ions at a fluence of 5 × 1011 ion/cm2. At elevated substrate temperatures, silver indium selenide (AIS) exhibited a nanorod -like structure. The optical and the structural properties of the irradiated films were studied using UV-VIS-NIR Reflection spectroscopy, atomic force microscopy (AFM), field emission scanning electron microscopy (FESEM), and XRD. The controlled fabrication of such densely distributed onedimensional nanorods on a Si substrate by using the ion beam technique, we believe, will open a variety of applications, such as nanoelectronics and optoelectronics devices.