Journal of the Korean Physical Society最新文献

The nonlinear evolution and intricate wave group dynamics of dust–ion acoustic waves (DIAWs) in a superthermal dusty plasma are explored through the analytical framework of the Gardner equation to incorporate both quadratic and cubic nonlinearities. The influence of self-interaction effects on wave packet modulation is analyzed through the derivation of a nonlinear Schrödinger equation (NLSE), which reveals the conditions under which modulational instability emerges. Our analysis reveals that the superthermal parameter strongly influences wave dispersion and significantly modifies the modulational instability regime within the relevant parameter space. Numerical simulations provide a spectrum of nonlinear wave structures, including solitons, double layers, table top solitons, breathers, and rogue waves, demonstrating complex wave dynamics under weakly nonlinear conditions.

The findings of the research on radiant heat and chemical reactions contribute to anticipating and managing fluid manners in non-linear, porous settings, which is critical for refining and upgrading existing technologies. For this, we examined a double stratified effect through a non-Darcian porous medium of second-grade fluid over a non-linear impermeable slendering surface. Effects of variable thermal conductivity, non-linear thermal radiation, and second-order chemical reactions are included in this study. The modified leading equations are resolved with the bvp4c tool. A discussion is written regarding the pertinent parameters of concern and how they affect the boundary layers of momentum, temperature, and concentration. It is observed that velocity reduces due to the viscoelastic parameter and Darcy–Forchheimer number; on the other hand, it is improved for permeability. Temperature rises due to thermophoresis and Brownian motion and reduces for Prandtl number and thermal stratified parameter. Also, concentration reduces due to thermal and concentration stratification parameters. Additionally, new features about thermophoresis and Brownian motion are explained. The Sherwood number, Nusselt number, and Skin friction coefficient are also added and inspected by the table.

This paper presents a numerical method for solving Schrödinger equations with arbitrary potentials with the adoption of the quantum diagonalization scheme and basis functions in the discrete wavelet transform. The quantum diagonalization scheme, developed to solve the Hubbard model and so on, is known to allow the diagonalization of a Hamiltonian matrix of a much large size, because it does not require to maintain the entire matrix in memory. And, the adoption of wavelet basis functions enables representing eigenstates efficiently using a number of bases much smaller than the number of grid points to integral and reducing the computation time to perform the diagonalization process. With the help of another additional techniques, the method allows to find solutions of a Schrödinger equation much exactly and efficiently. The validity of the method and its efficiency depending on several conditions are proven and surveyed by applying it to several problems for which the exact solutions are known.

After the Fukushima accident, numerous portable radiation measurement devices have been introduced at customs sites, including airports and harbors, for radiation inspection. However, most of these devices have limitations in isotope identification and radiation imaging, which can compromise the safety of customs operations. In this study, we developed a prototype hand-held-type gamma imaging device (pHGI) for the Korea Customs Service. The pHGI was composed of a small-sized CZT detector capable of 4π Compton imaging, an RGB camera, and a battery pack, all housed within a dedicated case. An automatic isotope identification method, based on the Becquerel library, and a Compton imaging method were implemented in the graphical user interface program for the pHGI. The performance of the pHGI was experimentally evaluated under various source conditions. The results showed that the pHGI automatically identified all of the nuclides with high energy resolution (0.82% @662 keV). The pHGI was also capable of imaging all identified isotopes independently. It was confirmed that the pHGI can not only identify the radioisotopes but also localize radioactive materials. These findings suggest that the pHGI has the potential to improve the efficiency of the customs work and the safety of the workers in the customs sites.

The phase shift due to head-on collision (HOC), production of forced Korteweg-de Vries (FKdV)-soliton, and collision process of FKdV-soliton are investigated in the Saturn F-ring environment. The three-component unmagnetized dusty plasma system consists of kappa-distributed positive ions, Maxwellian electrons, and negatively charged dust grains. The extended Poincaré-Lighthill-Kuo (ePLK) method is used to derive two-sided Korteweg-de Vries (KdV) equations. The bilinear Hirota method is used to obtain the multi-soliton solutions of the KdV equations, as well as their phase shifts. The single-soliton’s higher-order positive phase shift is considerably enhanced by the rising density ratio of electrons to negatively charged dust grains, the increasing strength of the nonlinearity, and the growing effect of the plasma-particle polarization parameter. As the values of the plasma-particle polarization parameter get a boost, so does the double-soliton’s positive phase shift after the HOC. The formation of FKdV-solitons is significantly influenced by the relevant plasma parameters. Only the compressive hump-shaped solitons are generated in this investigation. The results obtained in the study may help to understand the consequences of HOC of counter-propagating dust-acoustic solitary waves in polarized space environments, particularly in cometary tails, pulsar magnetospheres, Earth’s magnetosphere, and Saturn’s rings, as well as in the laboratory experiments of dusty plasmas.

This study investigates the nuclear structure of Te and Xe isotopes using algebraic collective models. These mid-mass nuclei exhibit collective excitations ranging from spherical vibrations to varying degrees of deformation. Te isotopes are treated as near-spherical or weakly deformed systems and analyzed using the interacting boson model (IBM). The ({}^{118})Te isotope is described within the U(5) symmetry of the IBM, which represents spherical vibrational behavior. In heavier Te isotopes (A = 120–130), features intermediate between U(5) and O(6) symmetries appear, thereby indicating mixed-mode structures. These are modeled by introducing perturbative contributions from the O(6) Casimir operator into the U(5)-based Hamiltonian. The study also applies Iachello’s critical-point symmetry E(5), which characterizes the phase transition between spherical and (gamma)-soft shapes, to the ({}^{128})Xe and ({}^{130})Xe isotopes. Calculations of low-lying energy spectra and electromagnetic transition probabilities are used to assess consistency with E(5) symmetry. These results offer new insights into shape evolution in mid-mass nuclei and highlight the effectiveness of algebraic models in describing nuclear phase transitions.

This study investigates the propagation and dynamics of optical waves governed by the variable-coefficient nonlinear Schrödinger equation. As a fundamental model in nonlinear wave theory, the NLSE plays a pivotal role in describing wave phenomena across diverse fields, including nonlinear optics, quantum mechanics, and fluid dynamics. Its ability to capture the interplay between dispersion and nonlinearity makes it indispensable for modeling localized wave structures, such as solitons, rogue waves, and breathers, which are critical to understanding complex wave behavior in real-world systems. Wave dynamics, including rogue waves, need to be studied to keep people safe in the ocean and to understand how they work, which helps protect marine ecosystems and make good use of ocean resources. Using the well-known enhanced modified simple equation method, we are trying to trace specific solutions that explain basic wave patterns realized in nature and the experimental phenomena, such as optical solitons, Bose–Einstein condensates, and Plasma waves. This method uses the improved modified simple equation to address the variable-coefficient nonlinear Schrödinger equation. The enhanced modified simple equation method uses a traveling wave variable called (xi), which is written as (xi =gamma (t)xpm pi (t)). The values of γ and π change over time to show how each transition naturally happens. We can incorporate differentiable functions of time, (gamma (t)) and (sigma (t)), which renders this method highly effective for modeling more dynamic wave characteristics. Because it takes into account changes in wavelength and time, the enhanced modified simple equation method makes it easier to get more accurate answers. This work adds new features that get around methods that are static or not very flexible. The extended mapping method for this soliton equation gives us more exact solutions and helps us learn more about wave dynamics in nonlinear optics, fluid dynamics, and other areas of physics that are affected by wave modulation. The result adds to what we already know.

This study presents a computational analysis of entropy optimization in MHD Casson hybrid fluid flow with non-linear thermal radiation and the Cattaneo–Christov heat flux model over a curved stretching sheet. It also incorporates multiple linear regression analysis and explores the behavior of Silver (Ag) and Gold (Au) nanoparticles within blood flow. The important self-similarity variables are used to change the non-linear partial differential equation system into a simpler ordinary differential equation, which is then solved using the fourth-order Runge–Kutta method along with the shooting method and the Homotopy Perturbation Method. The semi-analytical results have been compared to numerical outcomes from the shooting method and existing literature as a limiting instance. Graphical projections are provided with the impact of active parameters including velocity, temperature, Bejan number, entropy production, skin friction, and streamline. The increasing magnetic field increases the Lorentz force, which counteracts the flow and decreases the velocity profile in the presence of a curved surface. Temperature profiles decline with rising thermal relaxation in both radiation models, but the impact is more effective in the case of non-linear radiation. The proposed system uses unique method by using regression analysis and correlation techniques with the Nusselt number and skin friction. According to the estimated regression skin friction coefficient equations, the related parameters (phi_{1} ,phi_{2} ,M,lambda ,S_{k}), and (Fr) have a positive sign on (C_{fs} {text{Re}}_{s}^{1/2}), whereas (K) have a negative sign on (C_{fs} {text{Re}}_{s}^{1/2}). The proposed research offers potential contributions for real-time biomedical applications, including heat control in blood flow, tissue repair, drug delivery, hyperthermia-based cancer treatment.

We present a Data Acquisition (DAQ) system architecture specifically designed for time-resolved X-ray scattering and spectroscopy experiments at the Femtosecond X-ray Scattering (FXS) endstation at the Pohang Accelerator Laboratory X-ray Free Electron Laser (PAL-XFEL). This system addresses the critical challenges associated with high data production rates, alignment of data from various devices, the demands for efficient data handling, and scalability of entire system. To enable rapid preliminary analysis and data visualization, we have implemented a real-time analysis approach prior to data saving. In addition, the system provides user-friendly data access and analysis capabilities, ensuring efficient exploration and utilization of the collected data.

Utilizing an anti-reflection coating on the lens surface to enhance the coupling efficiency, we employ the ABCD matrix formalism to derive analytical expressions for the coupling efficiency (CE) between a laser diode (LD) and both single-mode circular core dispersion managed fiber, i.e., dispersion-shifted fiber (DSF) and single-mode dispersion-flattened fiber (DFF), facilitated by an anti-reflection coated hyperbolic microlens (ARCHL) at the fiber tip. This coating is pivotal for maximizing efficiency. Although no prior theoretical work has utilized an anti-reflection coating on the lens surface to enhance coupling efficiency, it is essential to acknowledge its potential importance. By reducing reflections at the lens surface, such a coating can minimize loss and increase the overall efficiency of the coupling process. We assume that the distribution for both the source and the fiber follows a Gaussian field characterized by a single parameter, and ensuring maximum CE necessitates matching the transmitted spot size of the lens with that of the fiber. To address the non-Gaussian nature of the fiber’s field, we utilize the Petermann II spot size, enhancing the realism of our estimations. Investigations span two wavelengths, 1.3 μm and 1.5 μm. Here, we show the effects of anti-reflection coating on coupling optics by comparing the coupling efficiencies for the two cases with and without using the anti-reflection coating on the lens surface. Our straightforward method accurately predicts coupling optics performance with minimal computational effort. This simple, yet precise technique stands to greatly benefit system designers in the optical technology field.