Large Number Of Particles Research Articles

The in situ green synthesis of metal organic framework (HKUST-1)/cellulose/chitosan composite aerogel (CSGA/HKUST-1) and its adsorption on tetracycline

Abstract In this work, a strategy of in situ 3D hierarchical porous HKUST-1/cellulose/chitosan (CSGA/HKUST-1) composite aerogels were synthesized using ethylene glycol diglycidyl ether (EGDE) as a cross-linking agent. The effect of EGDE on CSGA/HKUST-1 and the adsorption of tetracycline (TC) was investigated: the composite aerogel (CSGA) was produced by the ring-opening reaction of the epoxy group of EGDE in alkaline solution. The chemical structure of CSGA/HKUST-1 composite aerogel was characterized by FT-IR, XRD and XPS.49.33 % mass loading of CSGA1/HKUST-1 was achieved and N2 adsorption and desorption experiment showed the BET specific surface area reached 694.514 m2 g−1. SEM observed the CSGA/HKUST-1 composite aerogel pores were filled with a large number of octahedral HKUST-1 crystal particles. CSGA/HKUST-1 composite aerogel has excellent tetracycline adsorption capacity (285.7 mg g−1), and the removal efficiency remained at 92.7 % after five cycles of adsorption–desorption. The pseudo-second-order kinetic model and Langmuir model adsorption mechanism was successfully concluded. This study can provide ideas for in situ synthesis of MOFs on 3D composite aerogel to prepare adsorption materials, improve the mass loading rate of MOFs and prevent MOFs from falling off, etc., and enrich the application of MOFs materials in the treatment of antibiotic pollutants.

Structural transitions in systems with a triple-well potential

Objectives. Recently studied phenomena in condensed matter physics have prompted new insights into the dynamic theory of crystals. The results of numerous experimental data demonstrate the impossibility of their explanation within the framework of linear models of the dynamics of many-particle systems, resulting in the necessity to account for nonlinear effects. Analyzing the dynamics of systems in condensed matter physics containing a sufficiently large number of particles shows that modes of motion can undergo changes depending on the potential of interparticle interaction. This is also reflected in the presence of domains with essentially chaotic phase space having a number of degrees of freedom N ≥ 1.5 and a certain set of interparticle interaction parameters. However, it is not only the dynamic model that appears to be strongly nonlinear. A similar nature of motion can be also observed in a static nonlinear many-particle system. The paper aims to study the influence of the external field specified by the interatomic triple-well potential on the equilibrium structure of a chain of interacting atoms.Methods. Methods of Hamiltonian mechanics are used.Results. Analytical expressions are obtained and analyzed for determining the phase portrait of the equilibrium structure of a chain of interacting atoms for various values of the parameter characterizing the local potential of the field in which each atom of the chain moves. Phase portraits of the equilibrium structure of the system are constructed in continuous and discrete representations of the equilibrium equations for various values of the parameter characterizing the local potential of the field in which each atom of the chain moves.Conclusions. It is shown that both periodic and random chaotic arrangements of atoms are implemented depending on the magnitude of the external field.

Few-to-many-particle crossover of pair excitations in a superfluid

Motivated by recent advances in the creation of few-body atomic Fermi gases with attractive interactions, we study theoretically the few-to-many-particle crossover of pair excitations, which for large particle numbers evolve into a mode that describes amplitude fluctuations of the superfluid order parameter (the “Higgs” mode). Our analysis is based on the hypothesis that salient aspects of the excitation spectrum are captured by interactions between time-reversed pair states in a harmonic oscillator potential. Microscopically, this assumption leads to a Richardson-type pairing model, which is integrable and thus allows a systematic quantitative study of the few-to-many-particle crossover with only minor numerical effort. We first establish a parity effect in the ground-state energy, i.e., a spectral convexity in the energy of open-shell configurations compared to their closed-shell neighbors, which is quantified by a so-called Matveev-Larkin parameter discussed for mesoscopic superconductors, which generalizes the pairing gap to mesoscopic ensembles and which behaves quantitatively differently in a few-body and a many-body regime. The crossover point for this quantity is widely tunable as a function of interaction strength. We then compute the excitation spectrum and demonstrate that the pair excitation energy shows a minimum that deepens with increasing particle number and shifts to smaller interaction strengths, consistent with the finite-size precursor of a quantum phase transition to a superfluid state. We extract a critical finite-size scaling exponent that characterizes the decrease of the gap with increasing particle number. Published by the American Physical Society 2024

3D Gaussian Ray Tracing: Fast Tracing of Particle Scenes

Particle-based representations of radiance fields such as 3D Gaussian Splatting have found great success for reconstructing and re-rendering of complex scenes. Most existing methods render particles via rasterization, projecting them to screen space tiles for processing in a sorted order. This work instead considers ray tracing the particles, building a bounding volume hierarchy and casting a ray for each pixel using high-performance GPU ray tracing hardware. To efficiently handle large numbers of semi-transparent particles, we describe a specialized rendering algorithm which encapsulates particles with bounding meshes to leverage fast ray-triangle intersections, and shades batches of intersections in depth-order. The benefits of ray tracing are well-known in computer graphics: processing incoherent rays for secondary lighting effects such as shadows and reflections, rendering from highly-distorted cameras common in robotics, stochastically sampling rays, and more. With our renderer, this flexibility comes at little cost compared to rasterization. Experiments demonstrate the speed and accuracy of our approach, as well as several applications in computer graphics and vision. We further propose related improvements to the basic Gaussian representation, including a simple use of generalized kernel functions which significantly reduces particle hit counts.

Efficient Production of Chondrocyte Particles from Human iPSC-Derived Chondroprogenitors Using a Plate-Based Cell Self-Aggregation Technique.

The limited capacity of articular cartilage for self-repair is a critical challenge in orthopedic medicine. Here, we aimed to develop a simplified method of generating chondrocyte particles from human-induced pluripotent stem cell-derived expandable limb-bud mesenchymal cells (ExpLBM) using a cell self-aggregation technique (CAT). ExpLBM cells were induced to form chondrocyte particles through a stepwise differentiation protocol performed on a CAT plate (prevelex-CAT®), which enables efficient and consistent production of an arbitrary number of uniformly sized particles. Histological and immunohistochemical analyses confirmed that the generated chondrocyte particles expressed key cartilage markers, such as type II collagen and aggrecan, but not hypertrophic markers, such as type X collagen. Additionally, when these particles were transplanted into osteochondral defects in rats with X-linked severe combined immunodeficiency, they demonstrated successful engraftment and extracellular matrix production, as evidenced by Safranin O and Toluidine Blue staining. These data suggest that the plate-based CAT system offers a robust and scalable approach to produce a large number of chondrocyte particles in a simplified and efficient manner, with potential application to cartilage regeneration. Future studies will focus on refining the system and exploring its clinical applications to the treatment of cartilage defects.

Recent Patents on Particle Wettability Measurement and Improvement

Background: As the coal mining industry becomes more mechanized, it leads to a large number of coal dust particles suspended in the air, polluting the surrounding environment, accompanied by an increase in fine-grained low-rank coal particles and a low recovery rate of a large amount of organic matter in the particles, wasting resources. Objective: The study of particle wettability can have an impact on spray dust reduction and particle flotation efficiency. By adjusting the hydrophilicity of coal powder particles, the generation of suspended coal dust can be effectively suppressed. By adding surfactants, the flotation separation efficiency of coal particles can be improved. Method: This article introduces the measurement method of particle wetting properties and methods to improve the wetting properties of particles, providing a reference for studying the wetting properties of particles Results: The measurement of particle wetting properties is more accurate, simple, and convenient. Improving the wetting properties of particles by adding additives has significant implications for later dust reduction and particle flotation. Conclusion: This thesis provides an important basis for studying the wettability of particles, modifying the wettability and hydrophilicity of particles, providing specific guidance for improving the wettability of particles for spray dust reduction and particle flotation, and greatly improving industrial production efficiency.

Study on micromechanical behavior and energy evolution of granular material generated by latent diffusion model under rotation of principal stresses

In this study, advanced image processing technology is used to analyze the three-dimensional sand composite image, and the topography features of sand particles are successfully extracted and saved as high-quality image files. These image files were then trained using the latent diffusion model (LDM) to generate a large number of sand particles with real morphology, which were then applied to numerical studies. The effects of particle morphology on the macroscopic mechanical behavior and microscopic energy evolution of sand under complex stress paths were studied in detail, combined with the circular and elliptical particles widely used in current tests. The results show that with the increase of the irregularity of the sample shape, the cycle period and radius of the closed circle formed by the partial strain curve gradually decrease, and the center of the circle gradually shifts. In addition, the volume strain and liquefaction strength of sand samples increase with the increase of particle shape irregularity. It is particularly noteworthy that obvious vortex structures exist in the positions near the center where deformation is severe in the samples of circular and elliptical particles. However, such structures are difficult to be directly observed in sample with irregular particles. This phenomenon reveals the influence of particle morphology on the complexity of the mechanical behavior of sand, providing us with new insights into the understanding of the response mechanism of sand soil under complex stress conditions.

Study repair function of mucin-2 on the tight junction protein of uterine epithelial cells under bacterial endotoxins

To analysis repair function of mucin-2(MUC2) and glycoprotein particles on the tight junction protein of uterus under bacterial endotoxins. In this experiment, we showed that the thicker mucus layer of the uterus is used to prevent the translocation of endotoxin at 21d postdelivery. When endotoxin acts on the uterus to thin its mucous layer, the cells in the lamina propria of the uterus secrete a large number of glycoprotein particles at 27d postdelivery. Due to a significantly decrease in the expression of glycosyltransferase, the glycoprotein particles are incompletely glycosylation MUC2, which can interact with the cell membrane and are released in large quantities in the form of exocytosis. These glycoprotein particles can significantly repair tight junction proteins in the inter-cellular space and significantly increase the expression of Claudin-1, JAM (Junction adhesion molecule-A), E-cadherin, ZO-1(Zonula occludens-1) and desmosome proteins after endotoxin treatment. The results of the present study show that endotoxins can thin the uterine mucus layer and accelerate the release of incompletely glycosylated MUC2 from lamina propria cells. In inter-cellular spaces, MUC2 can increase its expression levels and distribution area to repair the tight junction structure of cells with larger gaps. Further strengthening of the barrier prevents endotoxin translocation by repairing the tight junction structure of uterine epithelial cells.

Lepton-flavor violation in the left-right supersymmetric standard model

In the standard model, the charged lepton-flavor violation (CLFV) processes are forbidden, so the observation of CLFV represents a clear signal of new physics that goes beyond the standard model. In this work, we focus on the CLFV processes lj−→li−γ and lj−→li−li−li+ in the left-right supersymmetric standard model (LRSSM). Considering the constraints of the updated experimental data, the numerical results show that the new contributions of SU(2)R gauge interaction and a large number of other new particles, such as the Z′ boson and double-charged Higgs bosons in LRSSM can make significant contributions to the CLFV processes lj−→li−γ and lj−→li−li−li+, which is much different from the ones predicted in other supersymmetry models. This work provides a theoretical base for finding the lepton-flavor violation phenomena in new physics. Published by the American Physical Society 2024

Josephson current through the SYK model

We calculate the equilibrium Josephson current through a disordered interacting quantum dot described by a Sachdev-Ye-Kitaev model fully contacted by two BCS superconductors, such that all modes of the dot contribute to the coupling, which encodes hopping and spin-flip processes. We show that, at zero temperature and at the conformal limit, i.e. in the strong interacting limit, the Josephson current is suppressed by UU, the strength of the interaction, as ln(U)/U and becomes universal, namely it gets independent on the superconducting gap. At finite temperature, instead, it depends on the ratio between the gap and the temperature. A proximity effect exists but the self-energy corrections induced by the coupling with the superconducting leads seem subleading as compared to the interaction self-energy and the tunneling matrix for large number of particles. Finally we compare the results of the original four-fermion model with those obtained considering zero interaction, two-fermions and a generalized qq-fermion model.

Modeling and Simulation of Sand Particle Trajectories and Erosion in a Transonic Fan Stage

Abstract In desert regions, the high concentrations of dust and sand particles carried by storms are sucked into aircraft engines, leading to severe erosion. This numerical study analyses the movement of sand particles and the erosion process in the front components of a high-bypass turbofan engine (HBTFE). The components include the Pitot intake, spinner, fan, core flow inlet guide vanes (IGVs), and secondary flow outlet guide vanes (OGVs). The study focuses on the engine operating conditions during takeoff from a Saharan airfield. The flow field data is obtained separately, and exported to an in-house particle tracking code based on the Lagrangian approach. The finite element method (FEM) is used to track the particles as they move through the mesh cells and determine the precise impacts and conditions to calculate the local erosion rates and material removal. Obtained results indicate large numbers of sand particles impacting the fan blade at high frequency from the hub up to approximately 80% of the span, due to their deflection by the Pitot intake lip and outer contour. The pressure side (PS) of the fan blade experiences extreme erosion rates, while the highest erosion rates occur at the leading edge (LE) and towards the trailing edge (TE). At the exit of the fan blade, a significant amount of particles pass through the OGVs and typically erode its PS, while fewer particles from the lower sections of the fan pass through the IGVs. These findings reveal the erosion-prone areas that need special coating protection.

Ameliorating the microstructure and properties of a Cu[sbnd]Cr alloy by introducing a high-temperature short-time treatment into the thermo-mechanical process

The optimization of process is essential for improving the overall properties of high-strength and high-conductivity Cu alloys. This study introduces a high-temperature short-time treatment (HTSTT, 850 °C/5 min) into the thermo-mechanical process of a CuCr alloy. Following the process of “solid solution - cold rolling - HTSTT - cold rolling - aging”, the tensile strength of the alloy increases from 450 MPa to 508 MPa, with the electrical conductivity increasing from 82.2 %IACS to 86.4 %IACS when compared to the conventional process of “solid solution - cold rolling - aging” under the same total deformation condition. The reasons for the improvement in the comprehensive properties of the alloy after introducing HTSTT are analyzed through microstructural characterization. The results indicate that the HTSTT promotes the occurrence of recrystallization, leading to grain refinement, which results in smaller grain sizes during subsequent processing. Additionally, the introduction of HTSTT changes the main texture of the alloy from 〈100〉//X to 〈111〉//X during the process, which is beneficial to enhancing the alloy's strength and electrical conductivity. More importantly, the HTSTT facilitates the precipitation of solute Cr atoms, leading to the formation of a significant quantity of nanoscale Cr particles, most of which are spherical with an average size of 27 nm. During the subsequent cold rolling process, these Cr particles effectively pin dislocations and promote their proliferation, leading to the precipitation of a large number of smaller Cr particles during the aging process, with an average size of 4.8 nm. These finer Cr particles are crucial for precipitation strengthening. This paper offers valuable insights into the microstructural optimization and performance enhancement of high-strength and high-conductivity Cu alloys.

Learning quantum properties from short-range correlations using multi-task networks

Characterizing multipartite quantum systems is crucial for quantum computing and many-body physics. The problem, however, becomes challenging when the system size is large and the properties of interest involve correlations among a large number of particles. Here we introduce a neural network model that can predict various quantum properties of many-body quantum states with constant correlation length, using only measurement data from a small number of neighboring sites. The model is based on the technique of multi-task learning, which we show to offer several advantages over traditional single-task approaches. Through numerical experiments, we show that multi-task learning can be applied to sufficiently regular states to predict global properties, like string order parameters, from the observation of short-range correlations, and to distinguish between quantum phases that cannot be distinguished by single-task networks. Remarkably, our model appears to be able to transfer information learnt from lower dimensional quantum systems to higher dimensional ones, and to make accurate predictions for Hamiltonians that were not seen in the training.

Green synthesis and antimicrobial study on the catechin-functionalized Fe3O4-Ag magnetic nanocomposites

In this study, catechin-functionalized Fe3O4-Ag nanocomposites were synthesized by a hydrothermal method. The motivation for this study was to develop a novel antibacterial agent with enhanced stability and biocompatibility. The objective was to create a nanocomposite combining the antimicrobial properties of silver with the antioxidant and bioactive characteristics of catechin. We hypothesized that the synergistic effect of catechin and Fe3O4-Ag would yield a highly effective antibacterial material against common pathogens. The obtained nanocomposites were characterized by TEM, SEM, AFM, XPS, XRD, FTIR and physical property measurement system (PPMS). TEM images indicated that catechin-functionalized Fe3O4-Ag nanocomposites have a spherical morphology with an average size of 25.7 nm. The SEM and AFM imaging revealed that the nanocomposites appear as a number of large particles with average diameter of 581 nm. XPS and XRD and FTIR measurement confirmed the presence of catechin components, Fe3O4 and Ag in the nanocomposites. Taken together, we conclude that the catechin-Fe3O4-Ag nanocomposites in this study have a jujube cake structure in which the Fe3O4-Ag alloy nanoparticles serve as the jujube and the condensed catechin form into the cake substrate. The antimicrobial test indicated the catechin-functionalized Fe3O4-Ag nanocomposites have obvious inhibitory effects on E.coli, S.aureus, and C.albicans.

Mean field limit for congestion dynamics

This paper addresses congested transport, which can be described, at macroscopic scales, by a continuity equation with a pressure variable generated from the hard-congestion constraint (maximum value of the density). The main goal of the paper is to show that, in one spatial dimension, this continuum PDE can be derived as the mean-field limit of a system of ordinary differential equations that describes the motion of a large number of particles constrained to stay at some finite distance from each others. To show that these two models describe the same dynamics at different scale, we will rely on both the Eulerian and Lagrangian points of view and use two different approximations for the density and pressure variables in the continuum limit.

Development Characteristics of Single Sand Body of Yan’An Formation in Western Ordos Basin

Abstract The precise characterization of the types and spatial distribution of strongly heterogeneous single sand bodies are a necessary prerequisite for the study of oil and gas reservoir formation. This article takes the Yan’an Formation in the western Ordos Basin as an example to systematically study the internal structure and profile distribution of strongly heterogeneous single sand bodies. The research results indicate that using mud interlayers, physical interlayers, and calcium interlayers as layered interfaces can effectively classify the single sand body types of each small layer in the Yan’an Formation. The drilling rate of a single sand body is between 50% and 85%, and the average number of sand layers is between 3 and 8. When two rivers intersect and are horizontally tangent, due to the mutual erosion of water flow, relatively thick sand bodies can be retained, ultimately resulting in a pattern of relatively thick on both sides and thin in the middle. The single sand body at the bottom is the most developed and has good continuity. In the transverse direction of the river, the continuity of a single sand body is relatively poor, and the extension range of a single sand body is 300m to 1200m. Along the river channel, single sand bodies are developed with good continuity, extending about 2km. The connectivity between the sand body and the well varies with the migration of the river in the transverse river profile of the research area. The lateral contact relationship of a single sand body determines the boundary of the river channel, and the profile characteristics of a single sand body also reflect its planar distribution. The intergranular pores of the Yan’an Formation sand body are relatively developed, and a large number of quartz particles offset the compressive stress of the rock. The corrosion of feldspar particles is relatively strong, retaining a large number of primary intergranular pores. There is a good quantitative relationship between the thickness of sand in a single level channel and the width of the channel. The control of the well network on the sand body is relatively small, and there is room for further densification of drilling. The vertical contact relationship of a single sand body in the Yan’an Formation of the research area can be divided into three modes: separation, stacking, and overlapping. Cut pile sand bodies with good connectivity have good production capacity. The different planar contact relationships reflect the degree of connectivity between channel sand bodies and wells, with lateral cutting type>docking type>isolation type. The side cut sand body has uniform longitudinal water absorption, small water absorption difference, and high-water drive degree. The isolation type has the greatest difference in water absorption rate and the lowest degree of water flooding.

Occurrence, abundance, and formation of atmospheric tarballs from a wide range of wildfires in the western US

Abstract. Biomass burning emits large numbers of organic aerosol particles, a subset of which are called tarballs (TBs). TBs possess a spherical morphology and unique physical, chemical, and optical properties. They are recognized as brown-carbon aerosol particles, influencing the climate through the absorption of solar radiation. Aerosol particles were collected from wildfire and agricultural-fire smoke sampled by NASA's DC-8 aircraft during the Fire Influence on Regional to Global Environments and Air Quality (FIREX-AQ) campaign in the western US from July to September 2019. This study developed an image analysis method using deep learning to distinguish TBs from other round particles that deformed on the substrate, based on the particles' morphological characteristics in transmission electron microscopy images. This study detected 4567 TBs, with most occurring < 10 h downwind of the emissions, and measured their compositions, abundance, sizes, and mixing states. The number fraction, mass fraction, and concentration of TBs in wildfire smoke corresponded to 10 ± 1 %, 10 ± 2 %, and 10.1 ± 4.6 µg m−3, respectively. As the smoke aged for up to 5 h after emission, the TB number fractions roughly increased from 5 % to 15 %, indicating that TBs are processed primary particles. We also observed TBs associated with pyrocumulonimbus (pyroCb) activity and various TB mixing states. This study reveals the abundance, as well as the physical and chemical properties, of a wide range of TBs from various biomass-burning events and enhances our knowledge of TB emissions, contributing to the evaluation of the climate impact of TBs.

基于 CFD 数值模拟的联合沙障间距优化与风沙流特征研究

Strong wind and sand activities will seriously damage the ecological restoration and agricultural safety production on the edge of desert areas, resulting in irreversible economic losses. In order to prevent and protect the agro-ecological environment in the wind-blown sand area, this paper constructs a combination of double-row vertical nylon net sand barrier and grass grid sand barrier. Through numerical simulation and wind tunnel experiment, the protection benefits of double-row vertical nylon net sand barrier and grass grid under different spacing conditions are analyzed, and the layout conditions with optimal spacing are obtained. The results show that when the spacing between double-row vertical sand barrier and grass grid is 5H-10H, the airflow velocity behind the double-row vertical sand barrier cannot be fully developed, the increase of airflow velocity is small, and the average wind prevention efficiency is above 85%. The effective protection distance com-pletely covers the entire combined sand barrier area, and a large number of sand particles near the surface are fixed to the grass grid, so the sand resistance rate is over 77%. The combined sand barrier has a good cooperative protection effect and achieves efficient wind prevention and sand fixation. The wind tunnel experiment verifies the reliability of the results. It also realizes efficient wind prevention and sand fixation under extreme wind and sand weather, and avoids sand burial on farmland and ecological restoration areas caused by extreme wind and sand weather.

Isolation, Identification and Genomic Analysis of Orange-Spotted Grouper Iridovirus Hainan Strain in China.

The orange-spotted grouper (Epinephelus coioides) is an important mariculture fish in China. However, in recent years, with the rapid development of aquaculture activities, outbreaks of viral diseases have affected the grouper aquaculture industry, causing severe economic losses. In the present study, we isolated and identified a virus from diseased, orange-spotted groupers from an aquaculture farm in Hainan Province, China. The isolated virus was identified as orange-spotted grouper iridovirus, hence named the orange-spotted grouper iridovirus Hainan strain (OSGIV-HN-2018-001). OSGIV-HN-2018-001 induces a cytopathic effect after the infection of mandarin fish (Siniperca chuatsi) brain clonal passage (SBC) cells. In addition, the cytoplasm of the OSGIV-HN-2018-001-infected SBC cells was found to contain a large number of hexagonal virus particles with a diameter of approximately 134 nm. Using the Illumina NovaSeq system, we assembled the sequence data and annotated the complete genome of OSGIV-HN-2018-001 (GenBank accession number: PP974677), which consisted of 110,699 bp and contained 122 open reading frames (ORFs). Phylogenetic tree analysis showed that OSGIV-HN-2018-001 was most closely related to ISKNV-ASB-23. The cumulative mortality rate of groupers infected with OSGIV-HN-2018-001 reached 100% on day 8. The spleens were enlarged and blackened after the dissection of the dying groupers. These results contribute to the understanding of the molecular regulatory mechanism of the iridovirus infection and provide a basis for iridovirus prevention.

Submicroscopic magnetite may be ubiquitous in the lunar regolith of the high-Ti region

Magnetite is rare on the Moon. The ubiquitous presence of magnetite in lunar soil has been hypothesized in previous Apollo Mössbauer spectroscopy and electron spin resonance studies, but there is currently no mineralogical evidence to prove it. Here, we report a large number of submicroscopic magnetite particles embedded within iron-sulfide on the surface of Chang’e-5 glass, with a close positive correlation between magnetite content and the TiO 2 content of the surrounding glass. The morphology and mineralogy of the iron-sulfide grains suggest that these magnetite particles formed via an impact process between iron-sulfide droplets and silicate glass melt, and ilmenite is necessary for magnetite formation. Magnetite in lunar glass is a potential candidate for the “magnetite-like” phase detected in the Apollo era and suggests that impact-induced submicroscopic magnetite may be ubiquitous in high-Ti regions of the Moon. Moreover, these impact-induced magnetite particles may be crucial for understanding the lunar magnetic anomalies and mineral components of the deep Moon.