Indian Journal of Physics最新文献

Raman spectroscopy is a widely used method for the analysis of various samples, including carbon-based materials. This study aimed to identify the number of layers and defects in graphene using micro-Raman spectroscopy. More specifically, this study examined the oxidation process of graphene under UV exposure. An investigation of the effect of the power density of the Raman excitation laser revealed a linear dependence between the ratio of I_2D/I_G and the power density of the excitation laser. Additionally, the absence of peak D due to the increase in power density provides evidence for the nondestructive nature of micro-Raman spectroscopy. Given the value of I_2D/I_G, one of the parameters for determining the number of layers in graphene, which reaches 1.39 at the edge, the findings indicate the possibility of an edge fold of single-layer graphene. During the oxidation process, the intensity and position of the D peak increase as a function of exposure time. Alterations in the graphene Raman spectrum, comprising the disappearance of the 2D peak and the appearance of the D peak, trace and confirm the oxidation process of the sample.

We are going to investigate the geodesic motion of charged particles in the vicinity of Schwarzschild anti-de-Sitter (S-AdS) spacetime with topological defects that admit temporal perturbation. We used the approximate Noether symmetry equation to insert the time conformal factor in the black hole without losing its symmetry structure. This type of insertion is necessary because the black hole radiates its energy and momentum in the form of gravitational waves and Hawking radiation. Along with the temporal perturbation, the S-AdS black hole (BH) is immersed in an external magnetic field. We conduct an in-depth examination of the dynamics of charged particles near a weakly magnetized and time conformal S-AdS BH. Our analysis involves calculating the shift in the position of the innermost circular orbit (ISCO) caused by both temporal perturbation and the presence of a magnetic field. Furthermore, we explore the influence of dark energy (DE) and angular momentum on the stability of these orbits. Additionally, we determine the effective force and escape velocity for a charged particle orbiting around the perturbed magnetized S-AdS BH. The application of time-dependent perturbation theory can extend our understanding to investigate the quasinormal modes (QNMs) of BH mergers.

In one of the approaches to quantization of gravity, the Wheeler–DeWitt equation for the wave function of the universe appeared long ago. Presently, the universe is considered as a micro-universe, a very tiny universe compared to the bigger outer universe to which it belongs. In this work, we will investigate quantum minisuperspaces within the framework of Finslerian spacetime that corresponds to spatially flat FRW background spacetime of the universe. Here, it is possible to convert the Wheeler–DeWitt equation for the wave function of this quantum minisuperspaces into the relativistic quantum mechanical equations, such as Dirac equation, Klein–Gordon equation etc., for the wave function of relativistic subatomic particles. The length scale indicating the smallness of the micro-universe appears in the quantum mechanical equation as the inverse of mass of the subatomic particle. Thus, the relativistic subatomic particles are shown here to be the quantum micro-universe within the bigger universe, such as the one we live in.

In photovoltaic research, bulk heterojunction organic solar cells have garnered significant interest as light harvesters. This increased attention underscores the importance of advance research in organic solar cell development. The present study considers an organic bulk heterojunction solar cell with P3HT:IC(_{60})BA as the active layer. Simulation studies are conducted using SCAPS 1D software. Initially, the software is standardized by comparing the experimental data of the solar cell structure, ITO/PEDOT:PSS/P3HT:IC(_{60})BA/ZnONPS/Al with the simulated characteristics of the solar cell. Subsequently simulation research is done to evaluate the impact of different hole transport layers (HTL) and electron transport layers (ETL) on device performance.The HTL materials considered in this study include PEDOT:PSS, CuI, and Cu(_{2}O) while the ETL materials include ZnO NPs, Sn(O_{2}), Ti(O_{2}), IGZO and PCBM. According to the results, the cell structure employing Cu(_{2}O) as the HTL and IGZO as the ETL performed better than all other combinations. The cell structure is further optimized to analyze the impact of material parameters on device performance.

The solar wind interacts with the earth magnetosphere and ionosphere, causing disturbances that create geoelectric fields in the Earth’s surface. These geoelectric fields link magnetospheric and ionospheric events, affecting the near-Earth environment. In the present study, we analyzed the ground- and space-based geoelectric field over Fresno, California, USA during three geomagnetic storms of different intensities, 19th February 2014 (moderate event), 17th March 2015 (intense event), and 17th March 2016 (weak event). We employed time series analysis and wavelet coherence analysis (WTC) to analyze fluctuations and investigate the strength of association and phase relationship between time series data of geomagnetic storms and geoelectric fields. We observed that ground-based magnetic and electric field fluctuations exhibited a distinct trend compared to space-based observations. WTC indicates that Ey (Space based Electric field) exhibits comparatively more enhanced power regions with solar parameters than EYt (Ground based elecrtic field). This is attributed to the impact of solar winds, which affect the ground electric field but have a less significant effect on the electric field in space.

In this manuscript we have mainly focused our study on the multiplicity distributions of projectile fragments and slowest target protons (black particles) released during the interaction of (^{84}Kr) with emulsion at 1 A GeV and their dependency on various target groups of the nuclear emulsion. In case of projectile fragments these distributions are described and have been replicated using a multi-source thermal model. The model makes the premise that collisions produce a large number of particle sources. Like a radioactive item, each source contributes a multiplicity distribution. The observations of the present study shows that the theoretical calculations utilising the multi-source thermal model and the experimental findings are in good agreement. In case of slowest target protons this study reveals a striking relationship between the target fragmentation processes and collision geometry with multiplicity distributions.