Indian Journal of Pure & Applied Physics (IJPAP)

Electrochemical Performance of Synthesized ZnS Microspheres for Super capacitor Applications

Sunil Kumar, Vinay Kumar, Sarita Sindhu, Mamta Bulla, Raman Devi, Lalit Kumar — Tue, 04 Mar 2025 00:00:00 +0530

The integrated energy conversion and storage mechanism are highly needed in future to fulfil the demand of energy consumption. The current investigation carried out to explore such a material which have immense potential in this sector. The present study explores the electrochemical charge storage behaviour of Zinc Sulphide (ZnS) as supercapacitor electrode. The synthesis was done via cost-effective, efficient, and straight forward reflexive method. The synthesized ZnS nanoparticle exhibit excellent crystallinity with 17 nm of average crystallite size and having microsphere morphology conveyed an excellent specific capacitance of 74 Fg^–1 at 1 Ag^–1 of current density and 72 Fg^–1 at sweep rate of 1 mVs^–1 along with remarkable rate capability that reflects the genuine potential of synthesized ZnS as an electrode for supercapacitor in energy storage.

Development and Characterization of RGO Ink for Microwave Absorber based Stealth Application

Megha Dixit, Anil Arora, Soumen Basu, R P Yadav, Hem Dutt — Tue, 04 Mar 2025 00:00:00 +0530

This research paper presents a method for synthesizing reduced graphene oxide (rGO) ink and investigates its morphological behavior based on sonication time. This study also explores the experimental verification of rGO's functionality as a tunable attenuator operating in the 1-8 GHz range. The synthesis process consists of three phases: synthesis of graphene oxide (GO), reduction of GO to rGO, and dispersion of rGO powder in a solvent. A comparative analysis of morphological and functional behavior is conducted by varying sonication time using X-ray Diffraction (XRD), Scanning Electron Microscope (SEM), and Energy Dispersive Spectroscopy (EDS). Results indicate that increased sonication time enhances the quality of multi-layered graphene, resulting in finer stacked layers and improved electrical properties. Also, measuring insertion loss at different biased voltages shows that r-GO ink can be used as a microwave tunable attenuator. This study provides valuable insights into the synthesis and characterization of rGO ink, highlighting its potential applications in the field of microwave electronics.

Chaotic Characteristics of RN Black Holes

Kumari Sammy, Sumita Singh — Tue, 04 Mar 2025 00:00:00 +0530

The nonlinear characteristics of general relativity are manifested in the chaotic behavior of black holes. Foot points of chaos can give an insight to understanding black hole phenomena. This paper aims to identify and analyze the chaotic behavior of Reissner Nordstrom(RN) black holes. A trajectory analysis of a test particle near Reissner Nordstrom metric performed using the Euler Lagrangian and action angle variable methods. The presence of homoclinic orbit implies the existence of chaos in dynamical system .We have evaluated the cutoff radial distance for the onset of chaotic motion for Reissner Nordstrom black holes metric with different charges. We have shown that geodesic motion around RN black holes with different charge values may become chaotic. A comparative analysis of the effective potential for Schwarzschild and RN black holes, along with an examination of homoclinic orbit, is presented in this paper. Therefore, we can say that these findings can lead to astrophysical application in many body relativistic models.

Optimizing Gallium Nitride (GaN) Based SOI-TF-FinFETs for Enhanced Linearity and Low Distortion in High-Frequency Applications

Praween Kumar Srivastava, Atul Kumar, Ajay Kumar — Tue, 04 Mar 2025 00:00:00 +0530

Gallium Nitride (GaN) based Fin Field-Effect Transistors (FinFETs) represent a breakthrough in semiconductor technology, especially for applications requiring high power, high frequency, and high efficiency. GaN is a wide bandgap semiconductor material known for its excellent electrical properties, including high electron mobility, breakdown voltage, and thermal stability. These characteristics make GaN an ideal candidate for next-generation electronic devices, particularly in RF and microwave communication, power amplification, and high-speed digital circuits. This paper investigates the GaN-SOI truncated FinFET (GaN-SOI-TF-FinFET) designed for high-performance linearity and low distortion, focusing on key metrics such as second-order and third-order transconductances (g_m2 and g_m3) values, third-order intercept points (IIP3), second and third harmonic distortions (HD2 and HD3), third-order intermodulation distortion (IMD3), and the 1-dB compression point (P1dB). By leveraging the high electron mobility and wide bandgap of GaN, we have optimized the fin dimensions and gate structures to enhance device performance. Our results indicate that the GaN-SOI-TF-FinFET shows significant improvements compared to conventional Silicon FinFETs. The g_m2, g_m3, HD2, HD3, and IMD3 values are reduced by 42.86%, 62.50%, 112.50%, 56.12%, and 56.25% respectively, while IIP3 and P1dB values are increased by 300% and 100% respectively. These parameter improvements indicate better power handling capacity and robustness of the proposed device, highlighting the potential of GaN-SOI-TF-FinFET for advanced RF and communication applications requiring high linearity and low distortion.

Compact High Gain and Bandwidth Enhanced RFID Reader Antenna for Handheld Applications

Abhishek Choudhary, Dr Deepak Sood — Tue, 04 Mar 2025 00:00:00 +0530

A compact UHF RFID reader antenna, designed for handheld applications, has been proposed to meet the requirements for high gain and wide bandwidth. The designed antenna exhibits linear polarization and delivers a maximum gain of 6.46 dBi along with a radiation efficiency of more than 90%. Furthermore, it achieves a maximum front-to-back ratio (FBR) of 19.75 dB and a 10 dB impedance bandwidth of 13.77 % spanning 125 MHz (from 845 to 970 MHz), thus covering the entire UHF RFID band (860 – 960) MHz making it suitable for various real-world applications such as in logistics, inventory management, asset tracking, healthcare and supply chain management. Notably, the antenna's compact profile, measuring (100×100×1.6) mm³ or equivalently 0.3λ×0.3λ×0.004λ relative to the center frequency of the operational band (907 MHz), facilitates seamless integration within handheld readers. A prototype of the design is fabricated on an FR4 substrate and its performance is experimentally verified.

Implementation of the Revised Pavlov’s Associative Learning Circuit to Avoid Parasitic Training Effects

ABHISHEK KUMAR, AKHILESH KUMAR, RAVI PUSHKAR — Tue, 04 Mar 2025 00:00:00 +0530

To enable organisms to learn behaviors from past experiences, biological systems rely on associative learning, a fundamental mechanism that forms connections between simultaneous events. Developing an electrical counterpart to model this associative learning phenomenon could be highly beneficial for edge AI applications. This study focuses on Pavlovian learning, an associative process in dogs where the sound of a bell becomes linked to food, leading to drooling as a response based on memory. Existing circuit models that attempt to replicate this phenomenon face limitations, especially in distinguishing between different stimuli types and often exhibiting a false learning effect without genuine learning. Consequently, these circuits only demonstrate associative learning under specific signal sequences, failing to do so with other configurations. To address this, we propose a novel circuit architecture using non-volatile memory components, designed to overcome sequencing limitations and enable true associative learning regardless of stimulus order. Simulation results obtained through PSPICE using 0.18 µm CMOS technology validate the functionality of the proposed circuits.

The Determination of X-ray Photon Absorption Properties of Some Human Tissues and Organs Using Monte Carlo method

Hasan Gulbicim, Huseyin Akan, Mustafa Cagatay Tufan — Tue, 04 Mar 2025 00:00:00 +0530

The interaction of photons with human tissues and organs is a critical area of study for healthcare professionals and medical physicists. This study investigates the photon absorption properties of various tissues and organs, across a broad energy range, with a particular focus on the X-ray energy range emitted from the Computed Tomography (CT) devices. The mass attenuation coefficient (µ_m), linear attenuation coefficient (µ), total atomic cross-section (σ_t,a), total electronic cross-section (σ_t,e), effective atomic number (Z_eff), effective electron density (N_eff), half-value layer (HVL), tenth-value layer (TVL), and mean free path (MFP) were calculated through an improved user code developed for this study. The results were compared to data obtained from the XCOM database, and showed excellent agreement, validating the accuracy of the method. In addition, the variations in radiation dose depending on the depth in some tissues and organs are also shown in this study. This comprehensive study provides a unique dataset for these radiation interaction quantities, which has not been collectively presented in previous literature. Our findings are expected to significantly enhance the understanding of photon interactions with human tissues and organs, particularly within the context of medical imaging and therapeutic applications.

The Role and Future of Leap Seconds in International Atomic Timekeeping

Navraj Poudel, Anjali Bisht, Aniket Gupta, Sanjeev Gautam, Poonam Arora — Tue, 04 Mar 2025 00:00:00 +0530

Time serves as a critical element in modern society, influencing numerous and diverse sectors such as finance and digital governance, telecommunications, navigation, and emerging technologies like Artificial Intelligence, and the Internet of Things (IoT). To ensure precise timekeeping, the ensemble of extremely accurate atomic clocks generate International Atomic Time (TAI) based on atomic frequency standards. However, the dynamic nature of the Earth's rotational speed introduces variations in earlier used time scale, Universal Time (UT1), which relies on the Earth's rotational dynamics.Therefore, to establish synchronization, Coordinated Universal Time (UTC) was formed, incorporating leap seconds to closely align with UT1. This paper explores the factors that sustain the link between UT1 and UTC, discusses the pros and cons of the leap second system, and highlights potential issues if it remains unaddressed.