Formation Process Research Articles

Ages, petrogenesis and metallogenesis implications of the Miocene adakite-like igneous rocks in the Beimulang porphyry Cu Deposit, southern Tibet

Understanding the petrogenesis of Miocene adakite-like igneous rocks is crucial for unraveling the formation processes of post-collision porphyry copper deposits within the Gangdese orogenic belt. This study focuses on the mineralogical, geochronological, and geochemical characteristics of the Beimulang Miocene adakite-like igneous rock series, with particular emphasis on two types of diorite porphyry (DP1 and DP2), to constrain their petrogenesis. Zircon U-Pb dating indicates that the monzogranite (MG), monzogranite porphyry (MGP), DP1, DP2 and granite porphyry (GP) were emplaced at 14.8 ± 0.1 Ma, 14.6 ± 0.1 Ma, 14.6 ± 0.1 Ma, 13.2 ± 0.1 Ma and 12.5 ± 0.1 Ma, respectively. The major element compositions of the Beimulang Miocene intrusions exhibit a differentiation trend. The Sr-Nd isotopic compositions of the MG, MGP, and DP1 align with the mixing line between the juvenile lower crust and the potassic lamprophyres. Conversely, the Sr-Nd isotopic compositions of DP2 and GP fall precisely on the Sr-Nd mixing line between DP1 and the ultrapotassic lamprophyres. Considering the reverse zoning of plagioclase in the DP1 and presence of high-Mg phlogopite in the DP2, we suggest that the Miocene magmatic series at Beimulang likely derived from the mixing of partial melts of Gangdese juvenile lower crust and mantle-derived potassic-ultrapotassic magmas. The increase in Th/Yb ratios from DP1, MG, MGP to DP2 and GP suggests that the mantle metasomatism material may have evolved from slab-derived fluids to melts derived from Indian crustal sediments. The magmatic water content and oxidation calculated from zircon trace elements, are nearly identical among the ore-causative MG and MGP, and the barren GP. However, the decrease in V/Sc ratios from the MG and MGP to GP indicates that magnetite-driven magma sulfide saturation leads to the depletion of chalcophile elements, significantly reducing the Cu mineralization potential of the GP. We suggest that the higher degree of magmatic evolution leads to the barren nature of Beimulang granite porphyry.

Effect of V concentration in TiSiN monolayer coating on chip formation mechanism and chip sliding velocity during dry turning of Ti–6Al–4V alloy

The current study examines how the self-lubricating characteristics of the novel TiSiVN coating affect the chip formation process and chip sliding velocity during the dry turning of Ti6Al4V titanium alloy. The serration bands tend to straighten at a cutting speed of 125 m/min, which is the main cause of the chips being straightened without tangling for both coated tools. TiSiVN coated tool accounts for higher chip sliding velocity due to the generation of lubricious phases, whereas the higher VS for uncoated tool indicates high tool wear at the highest cutting speed of 125 m/min. Further, r and θn tend to have an inverse relationship with VS, with 125 m/min cutting speed remaining an exception due to severe changes in tool wear dynamics. The reduction of friction helped to lower the localized strain along the shear bands and the effective stress at the beginning of the formation of the serrated tooth.

The H i Reservoir in Central Spiral Galaxies and the Implied Star Formation Process ∗ ∗ This is the fourth paper in the “From Halos to Galaxies” series.

The cold interstellar medium (ISM) as the raw material for star formation is critical to understanding galaxy evolution. It is generally understood that galaxies stop making stars when, in one way or another, they run out of gas. However, here we provide evidence that central spiral galaxies remain rich in atomic gas even if their star formation rate (SFR) and molecular gas fraction have dropped significantly compared to “normal” star-forming galaxies of the same mass. Since H i is sensitive to external processes, here we investigate central spiral galaxies using a combined sample from the Sloan Digital Sky Survey, Arecibo Legacy Fast ALFA survey, and the extended GALEX Arecibo SDSS Survey. After proper incompleteness corrections, we find that the key H i scaling relations for central spirals show significant but regular systematic dependence on stellar mass. At any given stellar mass, the H i gas mass fraction is about constant with changing specific star formation rate (sSFR), which suggests that H i reservoir is ubiquitous in central spirals with any star formation status down to M * ∼ 109 M ⊙. Together with the tight correlation between the molecular gas mass fraction and sSFR for galaxies across a wide range of different properties, it suggests that the decline of SFR of all central spirals in the local Universe is due to the halt of H2 supply, though there is plenty of H i gas around. These hence provide critical observations of the dramatically different behavior of the cold multiphase ISM, and a key to understand the star formation process and quenching mechanism.

Effects of Turbulence on Upper-Tropospheric Ice Supersaturation

Abstract Effects of turbulence on ice supersaturation at cirrus heights (>8 km) remain unexplored. Small-scale mixing processes become important for high Reynolds number flows, which may develop below the buoyancy length scale (10–100 m). The current study couples a stochastic turbulent mixing model with reduced dimensionality to an entraining parcel model to investigate, in large-ensemble simulations, how supersaturation evolves due to homogeneous turbulence in the stably stratified, cloud-free upper troposphere. The rising parcel is forced by a mesoscale updraft. The perturbation of an initially homogeneous vertical distribution of supersaturation is studied after a 36-m ascent in a baseline case and several sensitivity scenarios. Turbulent mixing and associated temperature fluctuations alone lead to changes in ensemble-mean distributions with standard deviations in the range 0.001–0.006, while mean values are hardly affected. Large case-to-case variability in the supersaturation field is predicted with fluctuation amplitudes of up to 0.03, although such large values are rare. A vertical gradient of supersaturation (≈10−3 m−1) is generated for high turbulence intensities due to the development of a dry-adiabatic lapse rate. Entrainment of slightly warmer (less than 0.1 K) environmental air into the parcel decreases the mean supersaturation by less than 0.01. Supersaturation fluctuations are substantially larger after entrainment events with an additional small offset in absolute humidity (by ±3.5%) between the parcel and environmental air. The predicted perturbations of ice supersaturation are significant enough to motivate studies of turbulence–ice nucleation interactions during cirrus formation that abandon the assumption of instantaneous mixing inherent to traditional parcel models. Significance Statement The purpose of our study is to investigate the effects of microscale turbulence on ice supersaturation in the upper troposphere. The associated variability in temperature and moisture fields is not resolved in cloud models and cannot easily be represented in terms of large-scale flow variables. We specify the conditions in which turbulent mixing and entrainment cause substantial variations in distributions of supersaturation. These include high turbulence intensity, strong atmospheric stability, and large moisture gradients. Our results suggest that turbulence may affect the strongly supersaturation-dependent ice formation processes in high-altitude clouds, pointing to the need to investigate cirrus formation in the presence of turbulence.

Insight into the formation mechanism of oxidation layer on the amorphous boron nanocluster surface

Boron (B) powder with a high-energy density can enhance the energy of propellants. It has two different forms, namely amorphous B and crystalline B, which have different behaviors during the oxidation. Especially, the oxidation layer (OL) on its surface inhibits the ignition and combustion (IC). To comprehend the formation of OL on the amorphous B nanocluster (BNC) and elucidate its oxidation mechanism, the investigation was conducted on the oxidation of amorphous BNC at various oxygen contents and temperatures (300~1900 K). An analysis of the initial oxidation products (OP), the formation process of the oxidation layer, the reaction path, and the oxidation rate were encompassed and the microscopic oxidation mechanism that cannot be observed experimentally was revealed. The morphology of B (crystalline or amorphous B) does not significantly affect the OP and the thickness of OL. The initial OP of amorphous BNC are BO2 rather than B2O3, and the ultimate OP consist of BO2, BO, and polymer BmOn (m≠1). The oxidation layer on the B surface exhibits a relatively thin thickness. The oxidation rates of two different types of B both follow a parabolic law. The atomic structure of B cluster has an important influence on the reactivity of B. The oxidation rate is influenced by both the surface structure and the oxygen content of amorphous BNC. Based on the above research, a novel oxidation mechanism of amorphous BNC was proposed.

Study of ash deposition characteristics of photovoltaic arrays taking into account the effect of photovoltaic module spacing and its effect on output characteristics: indoor experiment

The problem of ash deposition on the surface of photovoltaic(PV) arrays during actual operation seriously affects their power generation efficiency. Because traditional research does not consider the PV module spacing, it cannot reflect the actual PV array ash deposition problem. This study explored the influence of PV module spacing, combined with different tilt angles and inlet wind speeds, on the characteristics of ash deposition and power output of the PV array through indoor experiments. The study designed a set of experimental equipment for simulating the formation process of ash deposition on the surface of PV arrays and set up an experimental platform to measure the influence of ash deposition on the maximum output power (Pmax), open-circuit voltage (Uoc), and short-circuit current (Isc) of the PV modules. The findings indicate that as the tilt angle increases, the PV array experiences reduced ash deposition and increased output power. Conversely, higher inlet wind speeds lead to greater ash deposition and decreased output power. Moreover, widening the spacing between PV modules results in increased ash deposition and reduced output power. Notably, within the PV array, the front PV module accumulates more ash than the rear module, with larger particle sizes. These research findings have significant implications for optimizing PV array design and enhancing power generation efficiency.

ALMA high-resolution observations unveil planet formation shaping molecular emission in the PDS 70 disk

With two directly detected protoplanets, the PDS 70 system is a unique source in which to study the complex interplay between forming planets and their natal environment. The large dust cavity carved by the two giant planets can affect the disk chemistry, and therefore the molecular emission morphology. On the other hand, chemical properties of the gas component of the disk are expected to leave an imprint on the planetary atmospheres. In this work, we reconstruct the emission morphology of a rich inventory of molecular tracers in the PDS 70 disk, and we look for possible chemical signatures of the two actively accreting protoplanets, PDS 70b and c. We leverage Atacama Large Millimeter/submillimeter Array (ALMA) band 6 high-angular-resolution and deep-sensitivity line emission observations, together with image and uv-plane techniques, to boost the detection of faint lines. We robustly detect ring-shaped emission from 12CO, 13CO, C18O, H13CN, HC15N, DCN, H2CO, CS, C2H, and H13CO+ lines in unprecedented detail. Most of the molecular tracers show a peak of the emission inside the millimeter dust peak. We interpret this as the direct impact of the effective irradiation of the cavity wall, as a result of the planet formation process. Moreover, we have found evidence of an O-poor gas reservoir in the outer disk, which is supported by the observations of bright C-rich molecules, the non-detection of SO, and a lower limit on the CS/SO ratio of ~1. Eventually, we provide the first detection of the c-C3H2 transitions at 218.73 GHz, and the marginal detection of an azimuthal asymmetry in the higher-energy H2CO (32,1−22,0) line, which could be due to accretion heating near PDS 70b.

Jovian Vortex Hunter: A Citizen Science Project to Study Jupiter’s Vortices

The Jovian atmosphere contains a wide diversity of vortices, which have a large range of sizes, colors, and forms in different dynamical regimes. The formation processes for these vortices are poorly understood, and aside from a few known, long-lived ovals, such as the Great Red Spot and Oval BA, vortex stability and their temporal evolution are currently largely unknown. In this study, we use JunoCam data and a citizen science project on Zooniverse to derive a catalog of vortices, some with repeated observations, from 2018 May to 2021 September, and we analyze their associated properties, such as size, location, and color. We find that different-colored vortices (binned as white, red, brown, and dark) follow vastly different distributions in terms of their sizes and where they are found on the planet. We employ a simplified stability criterion using these vortices as a proxy, to derive a minimum Rossby deformation length for the planet of ∼1800 km. We find that this value of L d is largely constant throughout the atmosphere and does not have an appreciable meridional gradient.

The development of high-performance kinetic hydrate inhibitors by introducing N-vinyl caprolactam and vinyl ether homopolymers into PVCap

Low dosage kinetic hydrate inhibitors (KHIs) are a kind of alternative chemical additives to prevent gas hydrate formation in oil & gas production wells and transportation pipelines. In this work, a series of KHIs were experimentally synthesized with N-vinyl caprolactam (N-VCap) and vinyl ether including vinyl ether, vinyl n-butyl ether, vinyl isobutyl ether, triethylene glycol divinyl ether, with the mole ratio ranging from 9:1 to 5:5. The inhibition performance of new-synthesized KHIs on the formation process of methane hydrate were examined and compared with that of commercial N-vinyl caprolactam PVCap. Several ethylenediamine reagents were used as synergists and tested to improve the inhibition capacity of new-synthesized KHIs. The experimental results demonstrate that the introduction of ether groups on PVCap improves the performance of hydrate inhibitors. PVCap-VNBE (N-VCap: vinyl n-butyl ether = 5:5) showed the best inhibition performance for methane hydrate, which could extend the TVO to 1251 min under 6 K subcooling. N,N'-dimethylethylenediamine shows the best synergistic effect for PVCap-VNBE (5:5), and extends the TVO by 2.75 times at 7 K subcooling. Additionally, the relationship between hydrate inhibition performance and interfacial tension of newly-synthesized KHIs under high pressure were studied. It shows that the lower interfacial tension of KHIs would result in longer onset time, exhibiting better inhibition performance.

Evolution of the crack patterns in nanostructured films with subsequent wetting and drying cycles

Crack patterns in coatings present various morphologies as a signature of the matter to external stresses. Brittle films generally show a network of connected cracks due to a hierarchical formation process. On the contrary, non-sequential crack growth leads to a different morphology with few junctions. The present work focuses on the evolution of both crack networks under the effect of repeated stresses. The experimental work is performed through porous thin films over subsequent wetting and drying processes. The non-connected network of cracks is investigated through nanostructured films exhibiting compliant and elastic properties. Over repeated stresses, this crack network evolves until it reaches stabilization. The stabilization appears when the cracks stop growing and a shielding effect occurs. This behaviour is compared with a more classical connected network of cracks that do not evolve in the plane under the effect of repeated processes.

Adsorbate-Induced Adatom Formation on Au-Cu Bimetallic Alloys and Its Possible Consequences for CO2 Electroreduction

The adsorbate-induced formation of sub-nanometer clusters on transition-metal single crystals observed in previous high-pressure microscopic studies hinted at the in situ formation of unique active sites even on large nanoparticle catalysts. We propose that the adatom formation energy can be used as an energetic descriptor for the initial step toward the adsorbate-induced metal-cluster formation process. This descriptor can be efficiently computed using density functional theory (DFT) calculations and applied for screening and identification of metal catalysts where this phenomenon may play an important role in generating active sites in-situ. As a proof of concept, here, we construct an adatom formation energy database for three AuxCuy alloys (x:y = 3:1, 1:1, or 1:3) and eighteen adsorbates (H, C, N, O, F, S, Cl, Br, I, CHx, NHx (x = 1 – 3), CO, NO, and OH) commonly involved in catalytic reactions. The energetics of adatom formation were examined in all cases where (111) terrace, (211) step-edge, and (874) kink were the source of the adatom. We demonstrate that the presence of an adsorbate could alter not only the energetics for adatom formation but also the elemental nature of the preferred adatom being formed. Using our database, we identified promising systems which favor adsorbate-induced adatom formation under near-ambient conditions. Specifically, CO-induced adatom formation on all three Au-Cu alloy surfaces could occur under CO2 electro-reduction (CO2RR) conditions. This phenomenon offers a qualitative explanation for the experimentally observed CO2RR activity on Au-Cu alloy catalysts. Our methodology offers an easily expandable and efficient approach for large-scale catalyst screening with regards to adatom/cluster formation under reaction conditions and provides insight into the possible nature of active sites on alloy catalysts from a novel perspective.

Homogeneous CaAlg/PES hybrid Ultrafiltration membranes prepared with in situ ionic crosslinking and phase inversion method

Calcium alginate hydrogel/polyethersulfone (CaAlg/PES) hybrid membranes were synthesized via combining in situ ion crosslinking with phase conversion method. Once the Sodium alginate (NaAlg) uniformly dispersed in the casting solution contacted with Ca2+ dissolved in coagulation bath solution in the phase conversion membrane formation process, nanoscale CaAlg hydrogel was in situ formed through ion exchange and evenly dispersed in the membrane matrix. FT-IR and XPS were adopted to confirm the formation of CaAlg hydrogel distributed in PES membrane matrix. SEM, AFM, BET analysis and contact Angle analyzer were all used to characterize the surface changes of morphology, roughness and hydrophilicity in detail. Specific separation performance was also evaluated and compared by cross-flow ultrafiltration tests. Comprehensive analysis of the measured properties of all obtained membranes, when the content of NaAlg was 1.5wt%, the CaAlg/PES hydrogel membrane M32 had the most excellent performance. The pure water flux increased from 1967 to 2193L/m2hMPa, rejection rate of BSA was up to 99.87%, and RFR value was almost 76.83% after 4 cycles BSA filtration. XPS characterization of the membrane after filtration for 72hours showed that the retention rate of Ca (2P) reached 95%, which further proved the stability of the membrane operation.

Response of variation of electrical control parameters to coatings prepared in organo-silicon electrolyte by plasma electrolytic oxidation

This study aims to explore the influence of control parameters from the perspective of the amorphous ceramic coating formation process. Three preparation processes were preferred based on the thickness, appearance and corrosion resistance of the coatings by orthogonal experiment. The surface morphology, cross-sectional structure, phase composition and micro-hardness of PEO coatings were examined using scanning electron microscopy (SEM)/Energy dispersive X-ray spectroscopy (EDS), X-ray diffractometry (XRD) and hardness measurement techniques. Findings indicate that voltage exerts the most significant impact on coating thickness and appearance, whereas the influence of other parameters becomes more pronounced as the voltage increases. Three amorphous ceramic coatings prepared in 20 min with thicknesses of 27.4 μm, 83.2 μm and 193.3 μm increased the surface hardness of 6061 aluminium alloy by 6–8 times, and decreased the corrosion current density of 6061 aluminium alloy by 3 orders of magnitude in 1 mol L−1 HCl solution. Moreover, the thickening of the coating primarily occurs within a few minutes after the voltage reaches its peak, and high frequency and low duty ratio are prerequisites for better appearance under higher voltage conditions.

Formation mechanism and luminescence properties of silicon carbide nanowires with core-shell structure

For the preparation of SiC nanowires (SiC NWs) by carbothermal reduction, it is of great significance to study the formation mechanism of sic nanowires for process optimization and the controllable preparation. Although first-principles molecular dynamics (FPMD) can simulate systems of hundreds of atoms on a picosecond time scale, the results of FPMD are still insufficient to elucidate the formation mechanism of core-shell SiC nanowires. To make up this deficiency, this article has conducted Deep Potential Molecular Dynamics (DPMD) simulation on nanoseconds timescales with near FPMD accuracy for systems containing thousands of atoms, the results more concretively show the formation process of core-shell SiC nanowires. DPMD simulation results show when CO molecules react with SiO molecules, CO molecules are wrapped by SiO molecules to form agglomerates, SiO molecules in the agglomerates that can come into contact with the wrapped CO molecules will react with wrapped CO molecules to form the SiC core, and SiO molecules that in the outer layer of the agglomerates will disproportionate into the amorphous SiO2 shell. Furthermore, the formation mechanism of SiC nanowires was validated in combination with thermodynamics and experimental methods. Thermodynamic results show that vacuum conditions are favorable for the formation of SiO and CO and lower the temperature of SiC preparation. Finally, the core-shell structure of SiC NWs with good luminescence properties were successfully prepared by carbothermal reduction method using carbon black and silicon dioxide as raw materials under the pressure of less than 5 kPa.

Single-step template-free synthesis of fluoro-functionalized covalent organic frameworks with a tunable hollow structure for extraction of phthalate acid esters from human urine

Phthalate acid esters (PAEs) are recognized as endocrine disruptors, exhibit carcinogenic characteristics, and have the potential to impair fertility, thereby posing significant risks to both the environment and human health. Consequently, biomonitoring and exposure assessment of PAEs are of paramount importance. Presently, the majority of detection methods for PAEs are centered on aqueous matrices, and the development of techniques for the identification of PAEs in complex matrices remains an area of active research. This paper designed and synthesized a novel fluoro-functionalized hollow covalent organic framework (F-HCOF), characterized by a tunable hollow spherical structure and enriched with fluorine functional groups, through a one-step self-template approach, which effectively regulated the formation of the hollow structure. The synthesized F-HCOF with tunable hollow structures and abundant F functional groups provided efficient diffusion pathways and adsorption sites, facilitating robust and selective adsorption of the target PAEs. Using F-HCOF as a coating, a solid-phase microextraction method was developed to extract PAEs from complex matrices. The method exhibited limits of detection ranging from 0.0108 to 0.0581 ng L−1, with enrichment factors spanning from 2535.3 to 8985.3. The self-made F-HCOF fibers demonstrated the capability to effectively enrich PAEs under various interference conditions, further verifying their feasibility for practical sample analysis. This work provided a strategic approach for the synthesis of F-functionalized hollow COF adsorbents and explored the formation process of hollow spheres. It enables matrix interference-resistant analysis of PAEs, and offers a practical method for studying PAEs exposure and metabolism within the human body.

Unveiling the deterioration formation process of the rammed earth city wall site of the Ancient City of Pingyao, a World Heritage Site: occurrence, characterizations, and historic environmental implications

Unveiling the deterioration formation process of the rammed earth city wall site of the Ancient City of Pingyao, a World Heritage Site: occurrence, characterizations, and historic environmental implications

Influence of Black Hole Kick Velocity on Microlensing Distributions

The natal kick velocity distribution for black holes (BHs) is unknown regardless of its importance for understanding the BH formation process. Gravitational microlensing is a unique tool for studying the distribution of BHs in our Galaxy, and the first isolated stellar-mass BH event, OGLE-2011-BLG-0462/MOA-2011-BLG-191 (OB110462), was recently identified by astrometric microlensing. This study investigates how the natal kick velocity for Galactic BHs affects the microlensing event rate distribution. We consider a Maxwell distribution with various average kick velocities, as well as the consequent variation of the spatial distribution of BHs. We find that the event rate for the BH lenses toward the Galactic bulge decreases as v avg increases, mainly due to the scale height inflation. We focus on the unique microlensing parameters measured for OB110462, with microlens parallax π E larger than 0.06 for its long timescale of t E > 200 days. We calculate the expected number of BH events occurring with parameters similar to OB110462 during the OGLE-IV survey by Mróz et al. and compare it with the actual number that occurred, at least one. Our fiducial model predicts 0.52, 0.38, 0.18, 0.042, and 4.0 × 10−3 events occurring for v avg = 25, 50, 100, 200, and 400 km s−1, respectively, which suggests that the average kick velocity is likely to be v avg ≲ 100 km s−1. The expected number smaller than unity even at maximum might indicate our luck in finding OB110462, which can be tested with future surveys by, e.g., the Roman Space Telescope.

SHAMe-SF: Predicting the clustering of star-forming galaxies with an enhanced abundance matching model

Context. With the advent of several galaxy surveys targeting star-forming galaxies, it is important to have models capable of interpreting their spatial distribution in terms of astrophysical and cosmological parameters. Aims. We introduce SHAMe-SF, an extension of the subhalo abundance matching (SHAM) technique designed specifically for analysing the redshift-space clustering of star-forming galaxies. Methods. Our model directly links a galaxy’s star-formation rate to the properties of its host dark matter subhalo, with further modulations based on effective models of feedback and gas stripping. To quantify the accuracy of our model, we show that it simultaneously reproduces key clustering statistics such as the projected correlation function, monopole, and quadrupole of star-forming galaxy samples at various redshifts and number densities. These tests were conducted over a wide range of scales [0.6, 30] h−1 Mpc using samples from both the TNG300 magneto-hydrodynamic simulation and a semi-analytical model. Results. SHAMe-SF can reproduce the clustering of simulated galaxies selected by star-formation rate as well as galaxies that fall within the colour selection criteria employed by DESI for emission line galaxies. Conclusions. Our model exhibits several potential applications, including the generation of covariance matrices, exploration of galaxy formation processes, and even placing constraints on the cosmological parameters of the Universe.

Effects of solutes and additives on ice growth prevention in ice slurry production

Ice slurry is a promising functional fluid with high thermal energy density and high heat transfer rate. However, large ice particles in the ice slurry can cause blocking of tubes during ice slurry flow. Therefore, it is preferable to use fine ice particles to prepare ice slurry in many fields. In this study, ice slurries were generated from supercooled solutions containing additives, such as anti-freeze protein and polyvinyl alcohol, to prevent the increase in the ice particle size in the formation process of the ice slurry. The concentration of the solute and amount of the additive were varied as experimental parameters, and the size of the ice particles was evaluated. The average area of the ice particles decreased with the addition of the additives. In particular, anti-freeze protein was effective for generating fine ice particles in the ice slurry. However, the effects of the additives became weaker for higher concentration of the solute, and the size of the ice particles was almost the same regardless of the concentration of the solute and the amount of the additive. Moreover, it was found that particular properties, such as the freezing-point depression, kinematic viscosity of the solution, and effective latent heat of fusion, did not affect the size of the ice particles in the ice slurry generation process.

Global sparse attention network for remote sensing image super-resolution

Recently, remote sensing images have become popular in various tasks, including resource exploration. However, limited by hardware conditions and formation processes, the obtained remote sensing images often suffer from low-resolution problems. Unlike the high cost of hardware to acquire high-resolution images, super-resolution software methods are good alternatives for restoring low-resolution images. In addition, remote sensing images have a common nature that similar visual patterns repeatedly appear across distant locations. To fully capture these long-range satellite image contexts, we first introduce the global attention network super-resolution method to reconstruct the images. This network improves the performance but introduces unessential information while significantly increasing the computational effort. To address these problems, we propose an innovative method named the global sparse attention network (GSAN) that integrates both sparsity constraints and global attention. Specifically, our method applies spherical locality sensitive hashing (SLSH) to convert feature elements into hash codes, constructs attention groups based on the hash codes, and computes the attention matrix according to similar elements in the attention group. Our method captures valid and useful global information and reduces the computational effort from quadratic to asymptotically linear regarding the spatial size. Extensive qualitative and quantitative experiments demonstrate that our GSAN has significant competitive advantages in terms of performance and computational cost compared with other state-of-the-art methods.