Regular Distribution Research Articles

Elevation gradients alter vegetation attributes in mountain ecosystems of eastern Himalaya, India

The present study describes how vegetation (the tree layer) is shaped along the elevation gradients in the eastern part of the Indian Himalayan Region. Various vegetation attributes, distribution, population structure, and regeneration patterns of 75 tree species belonging to 31 families were studied. Tree species richness shows a low plateau (peaked between 1,300–1,500 m) with a linearly decreasing pattern above 1,500 m asl. Ericaceae was found as the dominant family, followed by Lauraceae and Rosaceae. The distributional pattern of species-to-genera ratio (S/G) did not follow any particular trends, while β-diversity increased along the elevation gradient. The Margalef index of species richness, the Menheink index of species richness, and the Fisher alpha were found to be highest at lower altitudes (1,000–1,500 m), while the Simpson index was highest at middle altitudes (2,600–3,000 m). Random distribution was shown by maximum tree species (47.3%), followed by a contagious distribution (42.9%), and regular distribution (10.8%). The regeneration of tree species was found to be good with a healthier number of seedlings (10.2%), fair (43.5%), poor (30.3%), while 16% were observed not regenerating. Acer laevigatum (1,500 m), Prunus nepalensis (3,300 m), Viburnum sympodiale (3,400 m) were among the new regenerating species at the respective altitudes. The population structure of tree species in terms of proportion of individuals in seedlings, saplings, and the adult class varied in all the elevation transects. Species with better regeneration on upper distribution limits have been recognized as probable for upward movement.

Acoustic performance of screens designed to act as metamaterials

Metamaterials are, nowadays, a mature field of research in acoustic and many applications with metamaterials have been developed in recent years. In metamaterials, the attenuation of sound is due to the interaction of the sound waves with their geometrically regular structures. The frequency at which the attenuation occurs is calculated with Braggs' law. This work presents sound attenuation measurements of structures made with metamaterials carried out in an anechoic chamber. The arrangements considered are both two- dimensional and three-dimensional: the 2D arrangement was obtained with a regular distribution of linear elements made with bars with diameters of 9, 15, and 20 mm; the 3D arrangement was obtained with a regular distribution of a lattice of spheres with a diameter of 23 mm. The results of the acoustic measurements are reported in terms of insertion loss in the range from 1000 to 10 000 Hz.

Suture Materials: A Perio Perspective

Sutures are natural or synthetic biomaterial devices used to connect blood vessels and align tissues [1]. Its primary function is to reunite and secure tissues after separation due to surgery or trauma. The purposes of wound closure include erasing the dead space, regular distribution of tension along the deep suture lines, keeping the tractile strength across the wound until the tissue tractile strength is sufficient and aiming to approximate the epithelial portion of the closure. Sutures are the most commonly used material for mechanical wound closure, even though there are other methods like staples, tape, and adhesive [2].

Non-random spatial organization of telomeres varies during the cell cycle and requires LAP2 and BAF

Spatial genome organization within the nucleus influences major biological processes and is impacted by the configuration of linear chromosomes. Here, we applied 3D spatial statistics and modeling on high-resolution telomere and centromere 3D-structured illumination microscopy images in cancer cells. We found a multi-scale organization of telomeres that dynamically evolved from a mixed clustered-and-regular distribution in early G1 to a purely regular distribution as cells progressed through the cell cycle. In parallel, our analysis revealed two pools of peripheral and internal telomeres, the proportions of which were inverted during the cell cycle. We then conducted a targeted screen using MadID to identify the molecular pathways driving or maintaining telomere anchoring to the nuclear envelope observed in early G1. Lamina-associated polypeptide (LAP) proteins were found transiently localized to telomeres in anaphase, a stage where LAP2α initiates the reformation of the nuclear envelope, and impacted telomere redistribution in the next interphase together with their partner barrier-to-autointegration factor (BAF).

Multi-hazard stochastic response analysis and reliability evaluation of a 5 MW monopile offshore wind turbine based on extended platform FAST-S

This study investigates the random dynamic response of a 5 MW monopile offshore wind turbine (MOWT) subjected to wind, wave and earthquake loads. Based on the aero-hydro-servo-elastic code FAST, a multi-field coupled simulation module considering earthquake, FAST-S, is developed for the fully coupled multi-hazard analysis of OWTs. Compared to the original FAST code, a seismic analysis module (SeismoDyn) and a soil-structure interaction (SSI) module (SoilDyn) have been supplemented in FAST-S. SeismoDyn is developed by modifying the Kane’s kinetic equation in the FAST, and the SoilDyn is developed through Winkler foundation model in order to consider the nonlinear SSI. Moreover, FAST-S has been validated by other recognized codes. Based on FAST-S, a fully coupled numerical analysis model of the NREL 5 MW MOWT is established, the random responses and reliability evaluation of the offshore wind turbine under wind, wave and earthquake loads are analyzed by probability density evolution method. The results show that the aerodynamic and hydrodynamic actions increase the damping of the wind turbine system, which has a certain effect on inhibiting the tower’s vibration caused by the earthquake. Therefore, compared with the coupled wind-wave-earthquake case, the sole earthquake case may be more unfavorable, and should be paid more attention to in high risk earthquake regions. The results show that the probability density functions of offshore wind turbine response under strong earthquakes obviously deviates from the typical regular distribution models. Based on the theory of equivalent extreme value event, the dynamic reliability of the offshore wind turbine is calculated. Seismic actions maybe the major factor in the design of the support structure. Nevertheless, owing to the aerodynamic and hydrodynamic damping effects of wind and wave loadings, the structural responses under wind-wave-earthquake are more moderate than ones subjected to solely earthquake. The strong seismic loads would cause significant complex variations of time-dependent probability density function of the OWT response.

Investigating the damage to masonry buildings during shield tunneling: A case study in Hohhot Metro

After prolonged service, masonry buildings constructed in the 1970s and 1980s often experienced significant deterioration in strength and stiffness. Excessive ground deformation caused by shield tunneling frequently leads to cracking in adjacent masonry buildings. Most studies have focused on the settlement and tilting caused by shield tunneling on masonry structures, failing to reflect the specific damages caused by shield tunneling. This paper employs a jointed masonry model in numerical simulations to simulate masonry buildings, considering the actual measurement data from the Hohhot Metro Line 1 project. It discusses a thorough investigation into the potential damages and cracking on masonry buildings that may occur during shield tunneling in masonry structures. It provides a detailed study of the specific forms of cracking in masonry buildings. Then, a comprehensive and in-depth analysis is conducted on the impact of bricklaying methods, mortar adhesive strength, and synchronous grouting pressure on buildings in the context of shield tunneling through structures. The results show that using the jointed masonry model can effectively reflect the cracking and damage situation of masonry structures during shield tunneling construction, providing valuable guidance for actual shield tunneling operations. The area of cracking damage caused by shield tunneling construction gradually increases from the top to the bottom of the building. It is concentrated above the doors and windows of the structure. Potential cracks around door and window openings extend from the upper-middle part of the openings towards both sides, forming a regular figure-eight distribution. With changes in the masonry construction method, grouting pressure, and mortar bond strength, the settlement and damage levels of the building also undergo alterations. Specifically, as the mortar bond strength increases from 30 kPa to 50 kPa, the maximum tensile strain of the masonry construction decreases to 0.11 %. Simultaneously, when the construction method of the building bricks transitions from A to B, the damage at the door and window openings on the west wall of the building gradually intensifies, resulting in a rise in the maximum tensile strain to 0.109 %. Furthermore, as the grouting pressure increases from 50 kPa to 300 kPa, the maximum settlement of the building walls decreases by 51 %, and the maximum tilt reduces by 48 %. However, this study did not account for the lintels and sills in the masonry building, which may lead to an overestimation of simulated strain data.

Discriminating the non-coordination between ecosystem service value and economic development and its spatial characteristics in central Yunnan urban agglomeration in the recent 30 years

Environmental issues have become one of the important topics affecting China and the world. As the world’s most populous country and the second-largest economy, China’s environmental conditions have significant impacts on global ecosystems and sustainable development. To accurately determine the relationship between economic development and the environment, explore the non-coordination and spatial characteristics between the two, and promote regional sustainable development. This study is based on land-use data from four periods: 1990, 2000, 2010, and 2020. It uses the dynamic measurement and value equivalent method to explore the characteristics of land-use changes and measure the value of ecosystem services in the Central Yunnan Urban Agglomeration. At the same time, the study uses the non-coordination degree model and hotspot analysis tools to identify the non-coordination between Ecosystem Service Value and economic development (Gross Domestic Product), and explore the spatial characteristics between them. The research results show that: (1) The main land-use types include cultivated land, forest land, and grassland, which account for more than 90% of the total proportion. The land types with a small proportion in the region are water areas, construction land, and unused land. (2) The development level of ecosystem service value presents four types of changes: fluctuating increase, fluctuating decrease, continuous increase, and continuous decrease. The regional spatial distribution shows obvious regional heterogeneity, overall presenting a spatial distribution pattern of “low in the middle, high around.” (3) The average index of non-coordination degree from 1990 to 2020 is 0.591, 0.635, 0.584, and 0.565, showing a coordinated non-coordination coupling type. The regional space presents a spatial pattern of “high in the central and western regions, low in the northeastern and southern regions.” (4) The hotspots of non-coordination are mainly concentrated in the central and northwest regions of the Central Yunnan Urban Agglomeration, while the coldspots of non-coordination are mainly distributed in the northeastern, western, and southern regions of the Central Yunnan Urban Agglomeration, showing a regular agglomeration distribution. This study suggests that it is necessary to balance and coordinate the relationship between regional economic development and the environment.

Kampung Janda: Konstruksi Sosial Media Online Terhadap Perempuan yang Pernah Bersuami di Kota Banjarbaru

The existence of public perception about the news of the nickname “widow village” in Banjarbaru City, apparently caused pros and cons in the community. This research aims to find out the social construction in online media towards “widow village”. The type of research is descriptive qualitative using a constructivism paradigm approach. Data collection used observation, interviews and documentation. Data analysis used Robert N. Entman's framing analysis model. The theories used are social construction of mass media and critical discourse analysis. The results of this study show that in the news search column delivered by online media such as Tribunnews.com, there is a regular distribution of news, varied titles and erratic release dates. After further investigation, there are only two news contents that are slightly different in the Tribunnews.com media. Meanwhile, the results of fieldwork in the dialectical process of social construction are shown in three simultaneous processes, namely internalization, objectivation, and externalization. Internalization shows how the outside community reflects the “widow village” from interactions and actions. Objectivation shows how people begin to understand what is constructed. Externalization shows how people show their views or attitudes when they have been constructed on the news of “widow village” at some time later. The conclusion that can be drawn is that some of the elements highlighted from the media's perspective are considered not only gender bias but also morality issues, such as one of the widowed female informants who is still angry and difficult to return to talking about the topic. It is important, as much as possible, to sort out which news is good and true with false or lies, don't just focus on images and news content and easily demean fellow beings, whether women or men.

Preparation and Peculiar Magnetic Properties at Low Temperatures of La1.85Sr0.15CuO4 Nanofibers.

Herein, the preparation process, morphology, structure, and magnetic properties of La1.85Sr0.15CuO4 (LSCO) cobweb-like nanofibers are reported. LSCO nanofibers with a regular grain size distribution are successfully prepared via electrospinning, followed by calcination. We conducted morphology analysis and elemental distribution using electron microscopy and energy-dispersive X-ray spectroscopy (EDS), respectively. Additionally, magnetic property testing was performed using a vibrating sample magnetometer (VSM) to confirm the superconducting properties of the samples. Interestingly, our samples exhibited a superconducting transition temperature, Tc, of 25.21 K, which showed some disparity compared to similar works. Furthermore, we observed a ferromagnetic response at low temperatures in the superconducting nanofibers. We attribute these phenomena to the effects generated by surface states of nanoscale superconducting materials.

NEW PERSPECTIVES ON OLD MATTERS: A REVIEW OF ARCHAEOLOGICAL AND CHRONOMETRIC DATA FROM ABRIGO DO SOL (MATO GROSSO, BRAZIL)

ABSTRACTBased on the study of the primary documentation related to the excavations carried out by Eurico Miller in the 1970s at Abrigo do Sol, Mato Grosso (Brazil), we propose a new reading of the stratigraphic and chronological information obtained from this rock shelter. Despite the apparent incongruity in the chrono-stratigraphic distribution of published dates, a detailed examination of the stratigraphy and field notes allowed us to identify a chronometric sequence with regular distribution between the Middle Holocene and the Late Pleistocene periods for the Abrigo do Sol site. We present here the original documents related to radiocarbon dating and their analysis. We finally show the implications of this study for understanding this site and the discussions related to the ancient settlements of the Amazon forest.

Corneal parameters in diabetics versus non-diabetics and correlation with various blood sugar parameters.

Aim: To compare corneal parameters in diabetics versus age-group-matched non-diabetics; also, to correlate these parameters with the duration of diabetes, glycated haemoglobin (HbA1c) levels, and severity levels of diabetic retinopathy (DR). Materials and methods: A comparative study was conducted at a tertiary eye-care center from January 2020 to December 2020. Two-hundred patients (400 eyes) with type-2 diabetes (100) and age-sex-matched non-diabetics (100) were included. Corneal morphological parameters like central corneal thickness (CCT), endothelial cell density (ECD), coefficient of variance (CoV), hexagonality (6A), and average cell area were recorded by specular microscopy. These parameters were correlated with the duration of diabetes, severity of disease based upon fasting blood glucose levels, HbA1c, and grade of DR. Mean and standard deviation were calculated, and regular distribution of continuous data was tested using independent sample t-test and ANOVA. Results: Mean ECD (2447.32 ± 269.89/mm2), 6A (45.03 ± 6.71%), and IOP (15.47 ± 2.02 mmHg) changed in diabetic cases and were significantly low in diabetics, whereas, mean average cell area (413 ± 50.19 mm2), standard deviation (167.05 ± 77.91), CCT (525.81 ± 36.69) and CoV (39.84 ± 15.59%), were significantly high in diabetics. Mean CCT had insignificant variation. Subgroup analysis within diabetics showed a statistically significant reduction of ECD, cell count, and 6A with increased duration of diabetes, poor glycaemic control, and raised HbA1c. Discussion: The corneal endothelial analysis is vital in daily clinical practice and provides valuable evidence concerning the viability of corneal endothelium in various intraocular surgeries. Uncontrolled DM harms the cornea with 70% of diabetics resulting in complications like keratopathy. The study highlighted that the increased duration of diabetes raised HbA1c, and poor glycemic control negatively affected corneal morphology. Our study showed a definite reduction in ECD and 6A in diabetics compared to non-diabetics. Conclusion: A definite reduction in the corneal endothelial counts, cell density, and hexagonality was found in type-2 diabetics compared to non-diabetics. Abbreviations: DM = Diabetes Mellitus, CCT = central corneal thickness, ECC = endothelial cell counts, ECD = endothelial cell density, CoV = coefficient of variance, 6A = hexagonality, DR = Diabetic retinopathy, SD = Standard of deviation, IOP = Intraocular pressure.

Analyzing the Influence of Dividends on Share Prices in the Iraqi Stock Market from (2010 - 2020)

This study examines the relationship between dividend policies and stock prices among companies listed on the Iraq Stock Exchange from 2010 to 2020. This study utilizes a descriptive analytical approach, drawing on data from annual financial statements and disclosures published by the Iraq Stock Exchange. This study employs a simple linear regression model to analyze the impact of dividends per share and retained earnings per share on the market share price. The findings indicate a negative, statistically insignificant relationship between cash dividends and share prices, whereas retained earnings show a direct positive and significant correlation with stock valuations. Prior research in the Iraqi context has identified cash liquidity as the main determinant of dividend payout decisions, with shareholders favoring regular distributions, regardless of ownership. Studies also find a positive link between profit retention, investment opportunities, and dividends. However, broader challenges facing emerging stock exchanges, such as underperformance, speculation, and a lack of investor knowledge, can negatively impact market performance. This study provides a comprehensive, long-term analysis of dividend payout-stock price dynamics in the Iraqi market, offering valuable insights into how this relationship manifests in an emerging economy setting. The results contribute to the theoretical understanding of the factors driving stock valuation, and have practical implications for investment strategies and corporate dividend policies in Iraq and similar markets. Key recommendations include advertising campaigns to encourage savings, providing investment advisory services, and improving financial disclosure to build investor confidence.

PVA-TiO2 Nanocomposite Hydrogel as Immobilization Carrier for Gas-to-Liquid Wastewater Treatment

This study investigates the development of polyvinyl alcohol (PVA) gel matrices for biomass immobilization in wastewater treatment. The PVA hydrogels were prepared through a freezing–thawing (F-T) cross-linking process and reinforced with high surface area nanoparticles to improve their mechanical stability and porosity. The PVA/nanocomposite hydrogels were prepared using two different nanoparticle materials: iron oxide (Fe3O2) and titanium oxide (TiO2). The effects of the metal oxide nanoparticle type and content on the pore structure, hydrogel bonding, and mechanical and viscoelastic properties of the cross-linked hydrogel composites were investigated. The most durable PVA/nanoparticles matrix was then tested in the bioreactor for the biological treatment of wastewater. Morphological analysis showed that the reinforcement of PVA gel with Fe2O3 and TiO2 nanoparticles resulted in a compact nanocomposite hydrogel with regular pore distribution. The FTIR analysis highlighted the formation of bonds between nanoparticles and hydrogel, which caused more interaction within the polymeric matrix. Furthermore, the mechanical strength and Young’s modulus of the hydrogel composites were found to depend on the type and content of the nanoparticles. The most remarkable improvement in the mechanical strength of the PVA/nanoparticles composites was obtained by incorporating 0.1 wt% TiO2 and 1.0 wt% Fe2O3 nanoparticles. However, TiO2 showed more influence on the mechanical strength, with more than 900% improvement in Young’s modulus for TiO2-reinforced PVA hydrogel. Furthermore, incorporating TiO2 nanoparticles enhanced hydrogel stability but did not affect the biodegradation of organic pollutants in wastewater. These results suggest that the PVA-TiO2 hydrogel has the potential to be used as an effective carrier for biomass immobilization and wastewater treatment.

Histological Features of Neovaginal Epithelium after Vaginoplasty in Mayer-Rokitansky-Küster-Hauser Syndrome

To analyze the features of the epithelia coating neovaginas after vaginoplasty in women affected by Mayer-Rokitansky-Küster-Hauser syndrome STUDY DESIGN: We conducted a retrospective analysis of prospectively collected data. Women affected by Rokitansky syndrome who underwent neovaginal biopsy after vaginoplasty (McIndoe surgery, intestinal vaginoplasty, Vecchietti surgery, and Davydov surgery) were included. Macroscopic mucosal features were assessed through clinical examination and the Schilling test. Each biopsy specimen was prepared for examination by light microscopy and in some cases by scanning electron microscopy (SEM). Thirty-six patients (4 McIndoe, 2 intestinal vaginoplasty, 14 Vecchietti, and 16 Davydov) were included. All biopsies were performed without complications. In McIndoe's neovaginas, the mucosal microscopic features were similar to normal skin, with large areas of preserved epithelium, heterogeneous presence of dermal papillae, and superficial keratinization. The characteristics of the intestinal neovagina's surface were similar to those of a sigmoid colon, with well-shaped glands, cylindrical cells, and a secreting mucosa. In Vecchietti neovaginas, the surface the epithelium was flat and multilayered, highly similar to that of a normal vagina, with the presence of glycogen and superficial desquamation. On medium SEM magnification evaluation, the epithelium presented flattened polygonal cells. Finally, in Davydov neovaginas, none of the specimens had persistent mesothelial elements. The squamous neo-epithelium had regular aspects of differentiation with the presence of glycogen. At greater SEM magnification, microridges were evident, with a regular distribution. Each different technique of vaginoplasty leads to unique histological and structural features of the neovagina's mucosa. Knowledge of these elements must be the basis for the choice of the most appropriate intervention.

Generating Neutrosophic Random Variables Based Gamma Distribution

In practical life, we encounter many systems that cannot be studied directly, either due to their high cost or because some of these systems cannot be studied directly. Therefore, we resort to the simulation method, which depends on applying the study to systems similar to real ones and then projecting these results if they are suitable for the real system. The simulation process requires a good understanding of probability distributions and the methods used to transform random numbers that follow a regular distribution in the field [0,1] into random variables that follow them, so that we can achieve the greatest possible benefit from the simulation process and obtain more accurate and appropriate results for all conditions that arise. In previous research, we presented a neutrosophical vision of the process of generating random numbers that follow a regular distribution in the field [0, 1] and some techniques used to generate random variables, such as the inverse transformation technique that was used to generate random variables that follow a uniform distribution in the domain [a, b] and the exponential distribution, the rejection and acceptance technique, which was used to generate random variables that follow the beta distribution, and the mixed technique, which was used to generate random variables that follow the Poisson distribution. In this research, we present a neutrosophic study to generate neutrosophic random variables that follow the gamma distribution, a distribution that is frequently used in engineering applications.

A comparative study of spectral and luminescent properties of Eu3+-doped cation-deficient perovskite phosphors

Eu3+ is not only a major red-emitting activator, but also an excellent spectral probe ion. This work reports the Eu3+-sites and luminescence in the cation-deficient perovskite tungstates, A-site deficient SrLa2(Mg2W2)O12 [Sr1/2□1/2La(MgW)O6] and B-site deficient Sr2La2(MgW2)O12 [SrLa(Mg1/2□1/2W)O6]. The 7F0→5D0 excitation spectra of Eu3+ activators in two lattices were measured via pulsed dye laser. In SrLa2(Mg2W2)O12:Eu3+, there is only one 7F0→5D0 transition, which could be related to the Eu3+ center on La3+ sites; while, two 7F0→5D0 transitions in Sr2La2(MgW2)O12 indicate Eu3+ ions occupy Sr2+ in addition to La3+, resulting in the luminescent centers related to heterovalent substitution defects. The different Eu3+ sites make two phosphors exhibit different red luminescence properties. SrLa2(Mg2W2)O12:Eu3+ shows higher luminescent efficiency and thermal quenching due to its regular distribution of the activators resulting in lower dispersion losses of the energy transfer. The experimental results show that rare earth ions occupy different crystallographic positions in A-site and B-site deficient perovskite oxides, and this microstructure can be important for the corresponding luminescent properties.

Doxorubicin-sanguinarine nanoparticles: formulation and evaluation of breast cancer cell apoptosis and cell cycle

Background Therapeutic resistance fails cancer treatment. Drug-nanoparticle combinations overcome resistance. Sanguinarine-conjugated nanoparticles may boost sanguinarine’s anticancer effects. Methods Sanguinarine, HPMC-NPs, and doxorubicin were tested on Adriamycin-resistant MCF-7/ADR breast cancer cells, parent-sensitive MCF-7, and MCR-5 normal cells (DX). Results Regular distribution, 156 nm diameter, <1 μm average size, 100% intensity—SN is therapeutic. Furthermore, the obtained NPs showed PDI = 0.145, zeta-potential=-37.6, and EE%=90.5%. DX sensitized MCF-7 cells (IC50 = 1.4 μM) more than MCF-7/ADR cells (IC50 = 27 μM) with RR = 19.3. SA and SN were more toxic to MCF-7/ADR cells (overexpressed with P-gp) than their sensitive parent MCF-7 cells (IC50 = 4 μM, RR = 0.6 and 0.6 μM, RR = 0.7). MCR-5 normal lung cells were more resistant to SA (IC50 = 7.2 μM) and SN (IC50 = 1.6 μM) with a selection index > 2. Synergistic cytotoxic interactions reduced the IC50 from 27 μM to 1.6 (CI = 0.1) and 0.9 (CI = 0.4) after DX and nontoxic dosages (IC20) of SA and SN. DS and SN killed 27.1% and 39.4% more cells than DX (7.7%), SA (4.9%), SN (5.5%), or untreated control (0.3%). DS and DSN lowered CCND1 and survival in MCF-7/ADR cells while raising p21 and Casp3 gene and protein expression. Conclusions Cellular and molecular studies suggested adjuvant chemosensitizers SA and SN to reverse MDR in breast cancer cells.

Controllable reinforcement phase distribution at the grain scale via a simple precipitation process

Due to the inability of Zr to refine Al-containing Mg alloys, achieving pronounced grain refinement in cast AZ31 alloy has been a significant challenge for researchers. Surprisingly, we found that the reinforcement phases demonstrated a regular distribution at the grain scale after adding 0.9 wt% Nd and 0.3 wt% Y: Al2RE inside the grains and Al11RE3 agglomerated near the grain boundaries. Additionally, the grain size of AZ31 alloy was significantly reduced from 258 µm to 65 µm. The mechanisms of reinforcement phase distribution and grain refinement were explored through the combination of transmission electron microscope (TEM) and thermal analysis during the solidification process. Al2RE phase precipitates prior to α-Mg, and exhibits a specific orientation relationship with the matrix: 011̅0Mg∥011Al2RE，0002Mg∥22̅2Al2RE. This suggests that Al2RE serves as potentially effective heterogeneous nucleation sites for α-Mg. Moreover, Al11RE3 phase can restrict grain growth in the later stage of solidification. The tensile results show that a regular distribution of the reinforcement phase at the grain scale can not only effectively alleviate stress concentration, but suppress the formation of coarse twins by inducing grain refinement during alloy solidification process, significantly improving the strength and ductility of the alloy.

Wideband design and modeling of efficient multi-resonance reflective linear-to-circular polarization converter

Abstract A reflective linear-to-circular polarization converter based on dual frequency-selective structures (FSSs) is proposed and modeled to exhibit efficient wideband performance. The design utilizes a diagonal array of two connected circular patches as an effective anisotropy with regular current distribution in several successive resonances, resulting in orthogonal reflections with a 90° phase difference. The relevant upper-part characteristic is improved by using two separate square patches as a high-frequency resonator. This design with distinct key parameters leads to high overlapping and then excellent bandwidth and efficiency over 105% and 96%, respectively, with an axial ratio below 1.7 dB. A sophisticated equivalent circuit-admittance model including effective mutual coupling between two FSSs is extracted, featuring closed-form equations for the physical design. Different dielectric constants are studied on the converter, which offer controllable coverage in the range of 3–24 GHz (S, C, X, Ku, and K bands), variably. For actual validation, a very thin (0.04λ0 at 3.65 GHz) 8 × 8 array prototype was built and measured at different incident angles, showing angular stability up to 45° in 78% (6–14 GHz) bandwidth. This converter has potential applications in communication, spectroscopy, detection, and imaging in micro-, mm-, and THz-wave regions.

Kinetic Alfvén solitary waves in a low-β plasma with regularized kappa-distributed electrons

This study examines the characteristics of small-amplitude kinetic Alfvén waves (KAWs) in a typical magnetoplasma, where both ions and electrons are considered to have a regularized kappa distribution (RKD). The restrictions imposed on the standard Kappa distribution function will be removed by considering the RKD function. The RKD can also be used for kappa areas for spectral index κ &amp;lt; 3/2. We then use the Korteweg–de Vries equation to investigate the KAWs in this model, which we obtained from the reductive perturbation method. It is observed that the equation’s nonlinear and dispersive coefficients are functions of the Kummar functions and the cut-off parameter. It is found that the nonlinear and dispersive coefficients of this equation depend on the Kummar functions and the cut-off parameter. Due to the negativity of the coefficients of the wave equation, only compressive KAWs can exist and propagate in this model. The numerical results demonstrate a positive correlation between the soliton’s profile (amplitude and width) with an increase in the cut-off parameter. Conversely, the superthermality has a negative influence on the soliton profile. The influence of the soliton’s propagation angle on the magnetic field’s direction is investigated. It is found that the solitary wave will not propagate in the ambient when the propagation angle θ becomes 0 or 90. Overall, the results obtained from this research can be used in space and laboratory plasmas with low β that have non-Maxwellian electrons.