System Of Spheres Research Articles

Investigating Quantum Confinement and Enhanced Luminescence in Nanoporous Silicon: A Photoelectrochemical Etching Approach Using Multispectral Laser Irradiation

This study explores electrochemical etching to form porous silicon (PS), which has diverse biomedical and energy applications. Our objective is to gain new insights and drive significant scientific and technological advancements. Specifically, we study the effect of electrochemical etching of P-type silicon using laser irradiation in a hydrofluoric acid (HF) solution. The formation of the nanoscale PS structure can be successfully controlled by incorporating laser irradiation into the electrochemical etching process. The wavelength and power of the laser influence the formation of nanoporous silicon (NPS) on the surface during the electrochemical etching process. The luminous flux is monitored with the help of a customized integrating sphere system and an LED-based excitation source to find the light flux values distributed across the P-type nanolayer PS wafers. Analysis of the NPS and luminescence characteristics shows that the laser bandwidth controls the band gap energy absorption (BEA) phenomenon during the electrothermal reaction. It is demonstrated that formation of the NPS layer can be controlled in this combined laser irradiation and electrochemical etching technique by adjusting the range of the laser wavelength. This also allows for further precise control of the numerical trend of the luminous flux.

Unstable Regions of Anisotropic Relativistic Spheres in Higher-Dimensions

Abstract In this work, we consider the collapse of a $\mathbb{D}$-dimensional sphere in the framework of a higher dimensional spherically symmetric space-time in which the gravitational action chosen is claimed to be somehow linked to the $\mathbb{D}$-dimensional modified term.
This work investigates the criteria for dynamical instability of
anisotropic relativistic sphere systems with
$\mathbb{D}$-dimensional modified gravity. The certain conditions are
applied that lead to the collapse equation and their effects on
adiabatic index $\Gamma$ in both Newtonian (N) and Post-Newtonian
(PN) regimes by using a perturbation scheme. The study explores that
the $\Gamma$ plays a crucial role in determining the degree of
dynamical instability. This index characterizes the fluid's
stiffness and has a significant i7mpact on defining the ranges of
instability. This systematic investigation demonstrates the
influence of various material properties such as anisotropic
pressure, kinematic quantities, mass function, $\mathbb{D}$-dimensional modified gravity parameters, and the radial profile of energy density on the
instability of considered structures during their evolution. This
work also displays the dynamical behavior of spherically symmetric
fluid configuration via graphical approaches.

Scattering of a spinning dielectric sphere to polarized plane waves

The exact expression of the wave vector inside a spinning homogeneous dielectric sphere illuminated by polarized plane waves is derived utilizing the “instantaneous rest-frame” hypothesis and Minkowski’s theory. On this basis, the analytical expressions of the electromagnetic field in the rotation sphere system are attained. The asymmetry of the system is discussed, in which the cause is emphasized. The influence of the polarization states and rotation angular velocity on the scattering are analyzed, including the optical rotation effect and photonic hook (PH). The results of this manuscript have extensive application prospects in optical tweezers, particle manipulation, and antenna design.

Effects of Changes in Pectin Constitution on Optical Properties and Firmness of Peach Flesh during Storage.

Understanding the fundamental light-sample interaction process is a crucial step toward the development of vibrational spectroscopy to determine fruit texture (i.e., firmness). This study aimed to investigate the effect of pectin constitution, including total pectin, water-soluble pectin, protopectin contents, and protopectin index (PI), on the optical properties and firmness of 'Baifeng' and 'Xiahui 8' peach flesh at the different softening degrees during postharvest storage of 6 days at 20 °C. The firmness of 'Baifeng' and 'Xiahui 8' peaches significantly (p < 0.05) changed with a decreasing rate from 90.3% to 92.2%. Peach firmness of these two cultivars correlated well with PI contents (r > 0.912) and showed good internal correlations with optical scattering properties. The light absorption coefficient (μa) and reduced scattering coefficient (μ's) at 600-1600 nm were measured using a single integrating sphere system combined with an inversion algorithm. This relationship of μa and μ's with peach firmness and pectin constitution was first analyzed. Notably, the specific μ's at 660 nm, 950 nm, 1203 nm, and 1453 nm showed a satisfactory prediction of peach firmness and PI of 'Xiahui 8' (R2 ≥ 0.926) and 'Baifeng' peaches (R2 ≥ 0.764), respectively. Furthermore, the prediction models were established based on partial least squares regression coupled with optical properties, and considerable prediction performances were obtained for tissue firmness (Rp2 ≥ 0.863) and PI based on μ's (Rp2 ≥ 0.802). Consequently, these results further verified that the spectroscopic prediction model for peach firmness could be related to the high correlations between PI in tissues and their optical scattering properties. Future research interests could include the development of optical absorption and scattering sensors for rapid and efficient determination of peach firmness.

THEORETICAL STUDY OF INDIVIDUAL PSYCHOLOGICAL ASPECTS OF INTERNET ADDICTED PERSONS

People's interest in information technology and its activities directly affect the behavioral structures, emotional sphere and nervous system of a person in connection with his time standards. In the studies of scientists of the world, the influence of the internet and the problems of emotional intelligence on the emotional sphere of a person in a virtual environment from various scientific and theoretical points of view have been considered, and the empirical parts of the above studies have been covered. in our work. People now spend more of their free time watching videos, playing games, shopping on the internet and providing various services on the internet than interacting with people, which leads to the fact that interpersonal communication goes into the virtual environment. As a result, the ability to control time and behavior in the virtual world decreases. During stay in the online environment, the emotional sphere of a person is stimulated, and the attitude towards the environment changes. Human emotional intelligence decreases. In the real world, the ability to understand people's feelings, reduce the ability to control their expressions, cyber addiction, acceptance of the culture of the virtual environment acquire negative sides, as a result, their emotional intelligence decreases. This article examines the problem of internet addiction, its significance today and the psychological aspects of its impact on internet users, and also analyzes the socio-psychological factors that contribute to the formation of internet addiction in the context of research by scientists. A theoretical analysis of the individual psychological aspects of people with internet addiction was also conducted. Research object: 206 teenagers, 1st-4th year students studying at the Jizzakh branch of the National University of Uzbekistan. Average age: 20.7 years. Results: A group of teenagers prone to internet addiction are less aware of the place and place of using speech in interpersonal communication, which is an activity learned earlier in ontogenesis, and the opposite is observed in those prone to Internet addiction. Such people often make mistakes in interpreting the words of the interlocutor. The emotional intelligence of a teenager addicted to the Internet is significantly lower than the emotional intelligence of a teenager who uses the Internet less.

Statistical evaluation of electric field distributions in 3D composites with a random spatial distribution of dielectric inclusions

Electromagnetic applications of composites often impose constraints on the internal electric fields, such as an upper limit on the field strength to prevent local heating or dielectric breakthrough. However, owing to heterogeneity, the local fields in a composite differ from those in a homogeneous material. Moreover, they are accessible neither by experiment nor by effective medium theories, at least for arbitrary microstructures. In this work, we use numerical simulations to evaluate the electric field distribution and the effective permittivity for 3D systems of monodisperse impenetrable spheres dispersed in a continuous matrix phase. We restrict ourselves to loss-free dielectric materials and to a random spatial distribution of particles. Samples are placed in a parallel plate waveguide and exposed to a transverse electromagnetic wave. The local field amplitudes are calculated via the finite element method and are normalized to those of a homogeneous sample exhibiting the same effective permittivity and geometry. We analyze the distribution of the local electric field strength in both constituents, namely, particles and matrix. Thus, we evaluate mean values and standard deviations as well as the field strengths characterizing the highest and lowest percentiles. Increasing particle concentration or permittivity enhances heterogeneity, and so the local electric field strength in some domains can become much higher than its average value. The methods we apply here can also be used in further investigations of more complex systems, including lossy materials and agglomerating particles.

Constructing renewable energy sphere for efficient search

In the field of renewable energy (RE), traditional methods for understanding, development, and education have heavily relied on 2D table formats for data retrieval and presentation. However, these formats suffer from inefficiency and an inability to fully capture the relationships between variables. In response to this challenge, Li et al. (2022) demonstrated that their therapeutic 3D sphere system significantly outperformed the therapeutic 2D table in query processing time. Furthermore, Shih et al. (2020) utilized a T-test to underscore the superiority of the TED Talks sphere over the TED Talks 2D table format website in terms of convenience, query processing efficiency, usefulness, and intuitiveness. Building upon this foundation, this study referenced and enhanced the work of Li et al. by introducing a three-dimensional spherical visualization model driven by cluster-based binary integer programming (BIP). This novel approach resulted in a 58% reduction in information retrieval time and achieved an impressive 86.4% user satisfaction rating. It is worth noting that compared to the previous Systematic Review and Synthesis (SRS), user satisfaction experienced a significant 19% improvement. This improvement enhances the search efficiency for RE information, thereby fostering public awareness and development of RE. Taking energy supply-demand balance sheets as an example, this study demonstrates that the spherical retrieval system (SRS) constructed by the visualization 3D spherical model resolves the issue of inefficient retrieval in 2D table formats, and the newly added functionality of highlighting objects on the spherical surface intuitively illustrates the one-to-many relationships between individual RE supply and demand. To optimize hardware and software performance, data mining techniques are employed to cluster supply data, reducing complexity, and improving optimization efficiency. The experiment is that testers search for the same targets and compared the proposed 3D SRS with the Taiwan Power Company (Taipower) 2D website in terms of retrieval speed and accuracy. The statistical results of the T-test indicate that the proposed 3D SRS is more effective and accurate than the Taipower 2D website. The research findings indicate: 1. The new 3D SRS reduces query time by 58%. 2. Adopting the k-means algorithm for clustering and batch optimization can transform from an initially infeasible solution to finding the optimal solution within 12 s. This method also reduces computer software and hardware costs, providing effective solutions for relevant applications. These technologies can be used for the education, promotion, publicity, and dissemination of RE.

Stereoscopic spatial graphical method of Mueller matrix: Global-Polarization Stokes Ellipsoid

A Mueller matrix covers all the polarization information of the measured sample, however the combination of its 16 elements is sometimes not intuitive enough to describe and identify the key characteristics of polarization changes. Within the Poincaré sphere system, this study achieves a spatial representation of the Mueller matrix: the Global-Polarization Stokes Ellipsoid (GPSE). With the help of Monte Carlo simulations combined with anisotropic tissue models, three basic characteristic parameters of GPSE are proposed and explained, where the V parameter represents polarization maintenance ability, and the E and D† parameters represent the degree of anisotropy. Furthermore, based on GPSE system, a dynamic analysis of skeletal muscle dehydration process demonstrates the monitoring effect of GPSE from an application perspective, while confirming its robustness and accuracy.

Optical properties related to cell wall pectin contribute to determine the firmness and microstructural changes during apple softening

The modification of cell wall pectin is a major contributing factor to apple softening, associated with intensive variations of firmness and microstructure. Thus, a better understanding of the relationship between fruit optical properties, firmness, 3D microstructure and pectin is important for improving the optical detection of apple firmness. This work explored the optical properties in the wavelength range of 430 – 1650 nm related to cell wall pectin during apple softening, in order to better determine their firmness and 3D microstructural changes. An automatic single integrating sphere system was used to quantify absorption coefficient (μa) and reduced scattering coefficient (μs′). Micro-CT imaging, SEM and TEM were used to quantify the porosity, cell numbers, cell volume, volume fraction and microstructure of Fuji apples during storage. Firmness, pectin fractions, soluble solids content (SSC), titratable acid content (TAC), and moisture content were also measured. Results showed that depolymerization of pectin substances induces an increase in porosity (r = 0.97) and modification of cellular structure, leading to a decrease in firmness (r = 0.90). The reduction in firmness and cell numbers exhibited a strong positive correlation with both μa in the range of 1000 – 1650 nm and μs′ between 430 and 1000 nm with mean r of 0.88–0.96, whereas increases in covalent-soluble pectin (CSP) and porosity displayed a negatively correlated with these bands. The linear relationship indicates that Vis-NIRS at 980 nm could better predict apple firmness than μa or μs′ alone, with a coefficient of determination R2 of 0.97. Our findings suggest that the mechanism of optical technology for detecting apple firmness may be the interaction between tissue structure and pectin on μs′ and μa.

Effect of CPPU on optical properties of strawberry in near-infrared range during growth

To investigate the effect of CPPU (forchlorfenuron) on optical properties of strawberry during growth, the optical properties (absorption coefficient (μa) and reduced scattering coefficient (μs')) of strawberry treated with CPPU solutions at different concentrations (0, 2.5, 5.0 and 7.5 mg/L) were measured in white, color turning and red stages by using a single integrating sphere system over near-infrared wavelength range of 900–1700 nm. The physicochemical properties, i.e., single fruit weight, soluble solids content, firmness and moisture content, as well as microstructure of strawberry were also investigated. The results showed that in white stage, the μa of strawberry treated with 7.5 mg/L CPPU was significantly (p ≤ 0.05) lower than that of untreated strawberry at absorption peak of 1411 nm. In color turning stage, the μs' of strawberry treated with 5 mg/L CPPU was significantly lower than that of treated with 2.5 mg/L at absorption peaks of 975, 1197 and 1411 nm. In red stage, the μa of strawberry treated with 2.5 mg/L CPPU was significantly (p ≤ 0.05) different from that of treated with 7.5 mg/L at 1197 nm. The study indicates that the optical properties of strawberry were affected by CPPU, and it provides useful information for identifying CPPU treated strawberry.

The new world order and the Global South

Abstract The shift of power away from the West is often seen as a key element of the crisis of liberal international order. The reluctance by most non-Western powers to side with the West vis-à-vis Russia’s invasion of Ukraine has contributed to the notion that the emerging order will be shaped by a contested system of spheres of influence, geopolitical tensions, and a much smaller common denominator vis-à-vis the normative elements of global order. Yet views across the Global South vis-à-vis the liberal order are far more nuanced, and pointing to non-Western powers as a culprit for the crisis of global order would be simplistic. Indeed, many countries in the Global South tend to be less opposed to the values themselves that undergird liberal order but question the Western-centric ways in which the rules and norms are applied and the in-built hierarchies and inequalities of liberal order. The main challenge of existing structures of global governance thus does not seem to be non-Western countries’ rejection of the underlying rules, but the question of whether today’s system is capable of functioning in a genuinely multipolar order, where power and privilege are less concentrated than in the past. The recent ‘geopoliticization’ of the global economy and the emerging ‘tech war’ suggest this process of adaptation will be enormously difficult. At the same time, while specific subgroups are explicitly opposed to a rules-based order, there are few signs that the Global South—a concept of little analytical usefulness beyond denoting the non-West—would be interested or capable of articulating a genuinely novel or alternative approach sufficiently attractive to garner broad support.

Ising Paradigm in Isobaric Ensembles.

We review recent work on Ising-like models with "compressible cells" of fluctuating volume that, as such, are naturally treated in NpT and μpT ensembles. Besides volumetric phenomena, local entropic effects crucially underlie the models. We focus on "compressible cell gases" (CCG), namely, lattice gases with fluctuating cell volumes, and "compressible cell liquids" (CCL) with singly occupied cells and fluctuating cell volumes. CCGs contemplate singular diameters and "Yang-Yang features" predicted by the "complete scaling" formulation of asymmetric fluid criticality, with a specific version incorporating "ice-like" hydrogen bonding further describing the "singularity-free scenario" for the low-temperature unusual thermodynamics of supercooled water. In turn, suitable CCL variants constitute adequate prototypes of water-like liquid-liquid criticality and the freezing transition of a system of hard spheres. On incorporating vacant cells to such two-state CCL variants, one obtains three-state, BEG-like models providing a satisfactory description of water's "second-critical-point scenario" and the whole phase behavior of a simple substance like argon. Future challenges comprise water's crystal-fluid phase behavior and metastable states.

Stable Electron Spin Pan on Aromatic Oxalic Acid Radical

Comprehensive SummaryThe stability of organic radicals in ambient condition is important for their practical application. During the development of organic radical chemistry, the electron‐withdrawing and steric hindrance groups are usually introduced to improve the stability of radicals via reducing the reactivity of radicals with oxygen in air. Herein, the electron‐withdrawing carbonyl groups are introduced to construct a planar aromatic oxalic acid radical (IDF‐O8) with two‐dimensional electron spin pan structure. Interestingly, IDF‐O8 exhibited a low optical bandgap of 0.91 eV in film, however, the multiple quinone resonance structures between electron‐withdrawing ketone and phenol radicals contribute to the high stability of open‐shell radical IDF‐O8 without protection of large steric hindrance groups. Under the irradiation of 808 nm (1.2 W·cm–2), IDF‐O8 reaches 147 °C in powder state. This work provides an efficient synthesis route for the open‐shell electron spin pan system, which is different from the famous fullerene, carbon nanotube and graphene. The electron spin pan can be extended to spin tube or spin sphere system based on the design strategy of aromatic inorganic acid radicals in future.

Statistical theory of fluids confined in quenched disordered porous media.

We develop a theory to calculate structural correlations and thermodynamic properties of a fluid confined in a random porous solid medium (matrix). We used density functional formalism to derive an annealed averaged expression for the density profile and excess free energy of fluid arising due to random fields of a particular realization of the matrix. After performing the second average over the quenched-disordered variables, the excess free energy is organized to give one- and two-body potentials for fluid particles. The average over disorder reduces the system to an effective one-component system of fluid in which particles feel one-body (external) potential and interact via effective pair potential. The effective pair potential is a sum of the bare (the one in the pure fluid) and the matrix-induced potential. The resulting partition function involves only fluid variables. Equations are derived for fluid-fluid and fluid-matrix correlation functions and for free energy, pressure, and chemical potential of the fluid. The theory is applied to a model system of hard spheres and results for the effective pair potential, correlation functions, and thermodynamic properties are reported. The effective pair potential is found to be attractive at the contact and develops a repulsive peak before decaying to zero. Results for pair correlation function and structure factor are compared with simulation results for several fluid densities at two matrix densities. In all the cases, a very good agreement has been found.

Phase transition face-centered cubic crystal — homogeneous phase in helium

In this work, the characteristics of the phase transition face-centered cubic crystal — homogeneous phase in helium are calculated based on the correlation cell-cluster expansion. The theoretical data were compared with experimental data and good agreement was obtained. It is discussed the use of data on phase transitions in helium to estimate thermodynamic characteristics phase transition in a quantum system of hard spheres.

Neutron spectroscopy for Boron Neutron Capture Therapy beams characterization

Boron Neutron Capture Therapy (BNCT) is a therapeutic treatment for malignant tumors that utilizes the nuclear reactions that happen when thermal neutrons are captured by boron-10 atoms to selectively destroy designated cells. Boron-10 atoms are biochemically accumulated inside the tumor target, which is then irradiated with thermal neutrons.In recent years, the possibility to obtain accelerator based intense neutron beams has given a boost to the diffusion of BNCT also in Europe, removing the need of nuclear reactors. In this contest, the monitoring and characterization of the epithermal neutron beams dedicated to BNCT becomes an important issue.The directional neutron spectrometer called NCT-WES (Neutron Capture Therapy Wide Energy Spectrometer) is a single moderator neutron spectrometer composed of a polyethylene cylinder embedding six semiconductor-based detectors positioned at different depths along the cylinder axes. The position of the six detectors is studied in order to maximize the response of each one in a selected neutron energy range. The unfolding of the six simultaneous readings allows to reconstruct the incoming neutron energy spectrum as in a parallelized Bonner Sphere System. A cylindrical collimator situated in the front of the spectrometer makes the instrument sensitive to neutrons coming only from a given direction, which allows to exclude the contribution of the room scattered radiation. The experimental validation of the spectrometer, obtained through several measuring campaigns, is reported and discussed.

Internal quality evaluation of ‘Fuji’ apples during storage based on bulk optical properties or diffuse reflection and transmission spectra

The purpose of this study is to compare the performance of prediction models based either on the bulk optical properties (BOP) or with models based on the diffuse reflection and transmission spectra to assess the soluble solids content (SSC) or fruit firmness (FF) of ‘Fuji’ apples. Diffuse reflection and transmission spectra of 240 apples in 500–1000 nm were acquired using a self-constructed single integrating sphere system, from which the absorption coefficient (μa) and reduced scattering coefficient (μ′s) were determined. The relationships of μa, μ′s, and the reflection and transmission spectra with the SSC and FF were analyzed, and detection models were established using partial least squares regression coupled with characteristic wavelength selection. Results showed that neither the SSC nor the FF changed obviously during 80-days storage, and the μa and μ′s showed no monotonic increase or decrease pattern. The SSC prediction model based on μa spectra combined with the baseline correction method performed the best (R2p = 0.79, RMSEP = 0.62), while the model based on μ′s spectra was the best for FF (R2p = 0.67, RMSEP = 0.35 N). Overall, the accuracy of the model based on BOP in predicting internal quality was better than that based on reflection and transmission spectra from the same measurement.

Modeling order–disorder boundaries of colloidal dispersions in organic solvents using interaction force measurements

HypothesisThe formation of soft colloidal crystals, which are nonclose-packed ordered arrays of colloidal particles suspended in a solvent, is dictated by a single physical factor that yields a fixed threshold at order–disorder boundaries for different experimental conditions such as ion concentration, solvent type, and particle size. Identifying the determinant factor and its threshold value should enable the prediction of the critical concentrations of colloidal particles to form soft colloidal crystals. ExperimentsSoft colloidal crystals were fabricated using a series of monohydric alcohols as dispersion media and reflectance spectra were measured to locate order–disorder boundaries. The interaction forces acting between particles were also measured by employing atomic force microscopy. FindingsThe interparticle forces at the order–disorder boundaries exhibited a universal threshold that was independent of the solvent types including alcohols and water. Therefore, the determinant factor for the formation of soft colloidal crystals was determined to be the force acting between the particles. Furthermore, a priori calculation of this critical force and consequently the critical particle concentration in colloidal systems was demonstrated by referring to the pressure at the liquid-to-solid transition in a hard sphere system (Alder transition).

HR Sphere

In today's dynamic organizational landscape, efficient management of human resources is imperative for sustained growth and competitiveness. The HR Sphere (Employee Management System) is a comprehensive software solution designed to streamline and enhance various aspects of employee management within organizations. This abstract provides an overview of the purpose, features, benefits, scope, methodology, and outcomes of the HR Sphere system. The primary objective of the HR Sphere system is to address the challenges associated with traditional manual methods of employee management, such as attendance tracking, payroll management, and performance evaluation. By leveraging advanced technologies and automation, the system aims to improve operational efficiency, accuracy, and compliance while empowering both HR personnel and employees

Hydrodynamic correlation and spectral functions of perfect cubic crystals

We investigate the collective dynamics of the perfect cubic crystal by deriving from the hydrodynamic equations the time-dependent correlation and the spectral functions characterizing the fluctuations of mass and momentum densities. We show that the seven hydrodynamic modes of the perfect crystal can be identified from the resonances of these spectral functions. The comparison with those of a fluid is discussed. Using the numerical values of the thermodynamic, elastic, and transport coefficients computed in our previous paper (J Mabillard and P Gaspard 2024 J. Stat. Mech. 023208) for a system of hard spheres, the theoretical expressions for the correlation and spectral functions are compared to the same functions directly computed using molecular dynamics simulations. The excellent agreement between theory and simulation provides strong support for the microscopic hydrodynamic theory of perfect crystals based on the local-equilibrium approach. This work sheds light on the fundamental mechanisms governing the collective behavior of matter in the solid state.