Mechanism Of Transformation Research Articles

A review of the preparation and prospects of amorphous alloys by mechanical alloying

The preparation of amorphous alloys typically involves rapid solidification from a molten state. Since 1980, when Yermo and Koch first achieved the amorphization of alloys by mechanical alloying (MA), researchers worldwide have developed a strong interest in this technique, which allows for the amorphization of alloy components in a non-equilibrium state at room temperature without the need for a liquid phase. MA has been widely applied in the fabrication of both equilibrium and non-equilibrium materials over the past few decades, and it remains a crucial technique for the production of amorphous alloys. This review selectively summarizes research on MA-produced amorphous alloys reported over the past two decades. It explores key issues of MA amorphization from the perspectives of both the mechanism of amorphization and the design of amorphous compositions through MA. The first section primarily elucidates commonly used methods for designing amorphous compositions at present, while the second section expounds on the transformation mechanism of MA amorphization. The third section summarizes the influence of alloy element additions on its properties, and the fourth section mainly illustrates the contribution of computational advancements to the exploration of amorphous mechanisms and the design of amorphous compositions. Finally, prospects for the development trend of preparing amorphous alloys through MA are discussed.

Copper‐Catalyzed Enantioselective Hydrophosphorylation of Unactivated Alkynes

P‐stereogenic phosphorus compounds are essential across various fields, yet their synthesis via enantioselective P‐C bond formation remains both challenging and underdeveloped. We report the first copper‐catalyzed enantioselective hydrophosphorylation of alkynes, facilitated by a newly designed chiral 1,2‐diamine ligand. Unlike previous methods that rely on kinetic resolution with less than 50% conversion, our approach employs a distinct dynamic kinetic asymmetric transformation mechanism, achieving complete conversion of racemic starting materials. This reaction is compatible with a broad range of aromatic and aliphatic terminal alkynes, producing products with high yields (up to 95%), exclusive cis selectivity, and exceptional regio‐ and enantioselectivity (> 20:1 r.r. and up to 96% ee). The resulting products were further transformed into a diverse array of enantioenriched P‐stereogenic scaffolds. Preliminary mechanistic studies were conducted to elucidate the reaction details.

Transformative elastic metamaterials: Temperature-induced passband-to-bandgap conversion

Elastic metamaterials favor the wide bandgap generation, but their formation mechanisms impose certain constraints on the achievable locations and widths. To overcome this limitation, this study proposes an innovative method that optimizes specific passbands and subsequently transforms them into bandgaps through an external stimulus. As an illustration, two meta-beams with different third passbands are optimized. In addition, to examine the formation and transformation mechanisms of the optimized passbands, this study develops several meta-beam models, incorporating force neutralizers, moment neutralizers, and their hybrid combinations, which are modally equivalent to the optimized unit cells. Samples for the two optimized meta-beams are fabricated using a three-dimensional printing technique. The experimental measurements are conducted at both room temperature and elevated temperatures, and the results confirm that when the temperature increases to approximately 60 °C, the optimized third passbands transform into bandgaps. Furthermore, repeated thermal loading cycles substantiate the reversibility of this transformation, demonstrating a promising application potential of the proposed method to tunable broadband meta-beam designs.

Strategic priorities for digitalization of the mining sector of Kazakhstan

Global uncertainty has transformed the economy of Kazakhstan, which is striving to become a center of innovative development in Central Asia. According to the authors, one of the reasons for the raw material orientation of the country's economy, along with the predominance of energy-intensive types of production, is the technological backwardness of the mining sector. The article shows that the strategic goal of the Kazakhstan mining complex to integrate into the world economy involves a focus on innovative development. PEST analysis of the most important micro- and macroeconomic factors made it possible to assess the current situation of enterprises. It was revealed that one of the significant reasons for the innovative lag in the mining sector of Kazakhstan is the lack of a strategic vision of digital transformation and change management mechanisms among enterprises. The authors conclude that the continuous complication of mining and geological conditions and the growing demands of stakeholders require enterprises to build internal production processes, promote R&D, improve the organization of analytical work based on an engineering and economic approach to the selection of tools for the digital basis of production, and active interaction with external partners and startups. It is substantiated that for further progress an integrated approach to the creation of intra-production digital competencies is necessary; enterprises should focus on organizational and technological transformation, including changes in the organizational structure and transformation of the business model. The results of the study are of interest to industrial enterprises when they develop proactive innovative strategies focused on reorganizing operational activities and increasing investment to promote business.

Mechanism exploration and model construction for small cell transformation in EGFR-mutant lung adenocarcinomas

Small-cell lung cancer (SCLC) transformation accounts for 3–14% of resistance in EGFR-TKI relapsed lung adenocarcinomas (LUADs), with unknown molecular mechanisms and optimal treatment strategies. We performed transcriptomic analyses (including bulk and spatial transcriptomics) and multiplex immunofluorescence on pre-treated samples from LUADs without transformation after EGFR-TKI treatment (LUAD-NT), primary SCLCs (SCLC-P) and LUADs with transformation after EGFR-TKI treatment (before transformation: LUAD-BT; after transformation: SCLC-AT). Our study found that LUAD-BT exhibited potential transcriptomic characteristics for transformation compared with LUAD-NT. We identified several pathways that shifted during transformation, and the transformation might be promoted by epigenetic alterations (such as HDAC10, HDAC1, DNMT3A) within the tumor cells instead of within the tumor microenvironment. For druggable pathways, transformed-SCLC were proved to be less dependent on EGF signaling but more relied on FGF signaling, while VEGF-VEGFR pathway remained active, indicating potential treatments after transformation. We also found transformed-SCLC showed an immuno-exhausted status which was associated with the duration of EGFR-TKI before transformation. Besides, SCLC-AT exhibited distinct molecular subtypes from SCLC-P. Moreover, we constructed an ideal 4-marker model based on transcriptomic and IHC data to predict SCLC transformation, which obtained a sensitivity of 100% and 87.5%, a specificity of 95.7% and 100% in the training and test cohorts, respectively. We provided insights into the molecular mechanisms of SCLC transformation and the differences between SCLC-AT and SCLC-P, which might shed light on prevention strategies and subsequent therapeutic strategies for SCLC transformation in the future.

Application of a laccase-catalyzed oxidative coupling for the removal and detoxification of typical flotation reagent salicylhydroxamic acid

Residual organic flotation reagents in mineral processing wastewater (MPW) can pose environmental hazards and hinder the sustainable development of the mining industry. Laccase as a versatile biocatalyst can eliminate various recalcitrant contaminants from the environment, but its potential applications for the removal and detoxification of organic flotation reagents have until now been overlooked. Herein, the influence of superparamagnetic immobilized laccase (SPM-IMLac) on the enzymatic removal of salicylhydroxamic acid (SHA), a typical mineral flotation reagent, as well as the mechanism of this process have been explored for the first time. The results indicated that SPM-IMLac can effectively remove SHA over a broad pH range and this process follows the pseudo-first-order reaction kinetics. A methodology which combined high resolution mass spectrometry (HRMS) and a solid phase extraction (SPE) technique revealed that SPM-IMLac could catalyze a single-electron oxidation of SHA to generate self/cross-oligomers via radical-driven C-C and/or C-O-C covalent coupling pathways. The Vibrio fischeri bioluminescence inhibition assay and a total organic carbon (TOC) analysis corroborated that the SHA transformation was accompanied by detoxification and by a reduction in TOC of the reaction solution, the extent of which correlated with the extent of the oxidative coupling. Moreover, SPM-IMLac could be easily recovered and reused, while keeping its high removal efficiency of SHA in the actual MPW matrices. This study not only provides fascinating insights into the transformation mechanisms and environmental fate of SHA mediated by SPM-IMLac, but it also exploits a viable and sustainable approach for the remediation of organic flotation reagents-contaminated MPW.

The Contribution of Digital Preservation as a Digital Transformation Mechanism within the Scope of the Sustainable Development Objectives of the 2030 Agenda

This study reports how institutions in a contemporary context experiencing significant digital transformations face several challenges to keep their memory alive for the next generations. In this context, digital preservation becomes essential for institutions to preserve their history. Also noteworthy are the Sustainable Development Goals established in the United Nations 2030 Agenda, which focus on sustainable development directly related to digital preservation. This article aims to analyze how humanity should consider Objectives 9, 11, 12 and 13 of the 2030 Agenda, whose objectives are interrelated with the theme of this research work. The methodology used was a bibliographic survey on the Web of Science, Google Scholar and Brapci databases, with a qualitative approach and categorical analysis. It is concluded that the interrelationship of digital preservation through the tool of digital certification in documents in institutions can be used as a mechanism for digital transformation within the scope of the Sustainable Development Goals (SDGs) of the 2030 Agenda.

Transformation of iron-minerals from natural aquifer media by sulfate-reducing bacteria: Behavior, mechanism, and Cr(VI) removal

Sulfate-reducing bacteria (SRB) and iron minerals are widespread in subsurface environments, where their mediated Fe and S transformations are crucial for contaminant immobilization. However, the mechanism mediated by SRB to transform natural iron minerals into reduced iron–sulfur compounds and the contaminant removal capacity of the transformation products remain unclear. Herein, the mechanism of native SRB-mediated transformation of iron-minerals from natural aquifer media into biogenic ferrous sulfide (FeS) was revealed and the Cr(VI) removal performance of the transformation product was evaluated. The results showed that Fe2+ production, sulfate reduction, and sulfide production occurred sequentially (rather than simultaneously) in the liquid phase. This suggests new processes and mechanisms for iron-mineral transformation: first, iron minerals dissolve to produce Fe2+ under enzymatic action rather than sulfide reduction; then, the generated Fe2+ accelerates sulfate reduction by SRB, producing sulfide in large amounts; finally, sulfide combines rapidly with Fe2+ to produce FeS. Elevated temperatures markedly shortened the required transformation time to start: maximum Fe production occurred at 18–24 days, 6–12 days, and 0–6 days at 10 °C, 20 °C, and 35 °C, respectively. Ambient temperature strongly affected SRB community composition, with Desulfosporosinus dominant at 10 °C and 20 °C and Desulfotomaculales prevalent at 35 °C. Sequential extraction, scanning electron microscopy, X-ray photoelectron spectroscopy, and X-ray diffraction analyses confirmed FeS as the main transformation product, which exhibited a highly efficient Cr(VI) removal capacity. Extending transformation time or increasing transformation temperature enhanced the Cr(VI) removal capacity of the transformation product. In column experiments, in-situ stimulation of SRB growth in aquifer media is able to form FeS, the Cr(VI) removal capacity of FeS reached up to 90.1 mg(Cr(VI))/kg(media). These findings suggest that biostimulation of SRB to mediate the in-situ transformation of iron-minerals to FeS has great potential for remediation of contaminated groundwater.

Digital transformation and technology innovation: evidence from Chinese manufacturing listed enterprises

ABSTRACT The listed A-share manufacturing enterprises in China from 2010 to 2019 serve as the research samples in this study. Moreover, the influence mechanism and effect of digital transformation of enterprises on technology innovation are studied at the micro level. The digital transformation of enterprises can facilitate technology innovation, and this effect continues to be significant after a series of endogenous and robustness tests are performed, as indicated by the results of this study. For mechanism, digital transformation is capable of indirectly affecting technology innovation via three channels, including reducing costs, elevating the efficiency of human capital, and deepening R&D collaboration among enterprises. In-depth analysis suggests that the effect of digital transformation on technology innovation exhibits certain heterogeneity in the development level of regional digital economy and the capital intensity of enterprises. Furthermore, enterprises in areas with higher development level of digital economy and those exhibiting higher capital intensity better enjoy the stimulating effect of digital transformation on technology innovation.

Unraveling the residual sludge-mediated waste transformation and physiological regulation mechanism of Tetradesmus obliquus

The accumulation of residual sludge as process waste from water treatment engineering needs to be addressed urgently. Tetradesmus obliquus is an important algal species in the field of wastewater treatment. In this study, T. obliquus was cultured in different sludge extract to determine its ability to utilize wastes from the liquid phase and convert them into biomass, and to analyze the response of the microalgae to toxic stress using proteomics. The results showed that the sludge extract medium was superior to the BG11 medium in accumulating biomass, with dry weights, proteins and polysaccharides at least 1.09, 1.12 and 1.28 times higher than those of BG11 medium. In toxic group, T. obliquus reduced TOC from an initial 426.8±20.0 mg/L to 180.4±8.5 mg/L with a simultaneous 48.4 % reduction in toxicity. Toxic sludge extract produced greater damage to the photosystem of T. obliquus compared to the blank, significantly inhibiting the expression of two photosystem II core proteins, A0A383VSL5 (0.290 down) and A0A383V2Z3 (0.308 down), on day 5. However, these impairments were reversible, and at day 20, the expression of A0A383VSL5 was not inhibited, the inhibitory effect of A0A383V2Z3 (0.575 down) was attenuated. These results fill a gap on the treatment of various types of residual sludge by T. obliquus and provide promising strategies for microalgae treatment of residual sludge, whether non-toxic or toxic.

Time-dependent redistribution of soil arsenic induced by transformation of iron species during zero-valent iron biochar composites amendment: Effects on the bioaccessibility of As in soils

Zero-valent iron biochar composites (ZVI/BC) are considered as effective amendments for arsenic (As)-contaminated soils. However, the mechanisms of transformation of various soil As species during ZVI/BC amendments remain unclear. This study investigated As transformation in four soils (namely, GX, ZJ, HB, and HN) treated with ZVI/BC for 65 days under two soil moisture conditions, unsaturated and oversaturated. Results showed that the 65-day treatment was divided into two stages based on the variation of labile As content. Within 2 days (stage 1), ZVI/BC addition quickly reduced labile As content by 5.91–90.3 % in soils under unsaturated conditions. During days 2–65 (stage 2), labile As ultimately decreased by 0.06–0.31 mg/kg in GX, ZJ, and HB while increasing by 22.1 mg/kg in HN soil, due to its lower pH value and Fe content. The variations of labile As were attributed to changes in multiple Fe minerals and associated As species. In stage 1, the corrosion of ZVI/BC generated amorphous Fe oxides to immobilize labile As, resulting in the accumulation of meta-stable As. In stage 2, amorphous Fe oxides were transformed into crystalline Fe oxides, resulting in the release and re-precipitation of As along with transformation, thus redistributing immobilized As into labile and stable As, which was evidenced by multiple methods, including chemical extraction, XRD, and TEM-EDX. The elevated soil moisture condition would enhance the corrosion of ZVI/BC in stage 1, further forming a reductive environment to facilitate the transformation of Fe minerals in stage 2. Besides, As bioaccessibility in soils was reduced by 10.8–38.7 % after ZVI/BC treatment in in-vitro gastrointestinal simulations. Overall, our study revealed the time-dependent transformation mechanism of soil As species and associated Fe minerals under different soil moisture with ZVI/BC treatments, and highlighted the effectiveness of ZVI/BC as a long-term amendment for As-contaminated soils.

Behaviors and Mechanism of Volatiles Producing during Coal Pyrolysis with Calcium Oxide Loading: Insights from Model Compounds Analysis

Calcium is a highly effective catalyst for controlling the tar compounds produced during the pyrolysis of low-rank coal, forming valuable end products. However, the exact catalytic mechanism of calcium in coal pyrolysis remains unclear due to the complex nature of coal. In this study, the pyrolysis process and tar composition of lignite, both with and without the addition of calcium, were investigated across three distinct temperature intervals. The addition of calcium oxide increased the hydrocarbon content of tar by 16.39% in the low-temperature range and 26.53% in the intermediate-temperature range. Four model compounds containing different coal-related functional groups were selected to investigate the effects of calcium on pyrolysis performance and tar composition using thermogravimetric analysis, fixed bed reactor experiments, gas chromatography/mass spectrometry, in situ Fourier transform infrared spectroscopy, X-ray diffractometer, and X-ray photoelectron spectroscopy. The addition of calcium did not affect the thermal decomposition of polystyrene or polyethylene terephthalate; however, the primary pyrolysates underwent secondary reactions on the surface of calcium, which affected the composition of the liquid pyrolysis product. Meanwhile, calcium interacted with the carboxyl and phenolic hydroxyl groups in trimeric acid and phenolic resin to form carboxylates and phenates, which affected the thermal reaction and distribution of liquid products. The influence of calcium on the transformation mechanism of coal-related functional groups provides a theoretical basis for understanding the mechanism of calcium-catalyzed coal pyrolysis.

Hollow spherical Na3.95Fe2.95V0.05(PO4)2P2O7 suppressing inactive Maricite-NaFePO4 with ultrahigh dynamics performance

sodium ion batteries are considered as excellent energy storage battery materials with the characteristic of low cost and renewability. As a critical component of sodium-ion energy storage batteries, cathode materials have attracted great attention from scientists around the world. Recently, Na4Fe3(PO4)2P2O7 (NFPP) which offer a theoretical capacity of 129 mAh g-1 has garnered widespread attention. However, the formation of inactive maricite NaFePO4 (NFP) and low capacity Na2FeP2O7 (Na2FPO) during the synthesis process restricts the capacity utilization, while poor conductivity further limits its electrochemical performance. To address these issues, here, Na3.95Fe2.95V0.05(PO4)2P2O7/C (V0.05-NFPP/C) composite material was synthesized and assembled into cell for testing. A capacity of 114 mAh g-1 was given at 0.1C and rate performance also represent 90 mAh g-1 at 10C. Vanadium-ion improves the dynamic performance by inhibiting maricite NFP and participating in electrochemical reactions. Furthermore, sodium-ion storage mechanism of V0.05-NFPP/C was revealed by ex-situ XRD patterns with the assistance of first-principles calculations, and the phase transformation mechanism during the sintering process was explored.

Molecular insights into biological transformation mechanism of sulfathiazole by Chlorella sorokiniana: Deciphering the uptake, translocation, and biotransformation

As a sustainable approach to wastewater treatment, microalgae have been extensively used to degrade antibiotics. However, the underlying mechanisms involved in the degradation process remain unclear. Therefore, this study investigated the biotransformation mechanism of sulfathiazole (STZ) by Chlorella sorokiniana (C. sorokiniana) at the molecular level. The results show that C. sorokiniana could efficiently degrade STZ, achieving a maximum degradation rate of 94.74 %, mainly through biodegradation routes. Transcriptome analysis has elucidated the potential biological transformation mechanisms driving the degradation of STZ by microalgae, focusing on the uptake, translocation, and biotransformation as key metabolic processes. In particular, STZ induced the up-regulation of genes associated with cell adhesion, membrane protein, and lipopolysaccharide, suggesting their involvement in the uptake of STZ by microalgae. Furthermore, ABC, MATE, and MFS transporters were identified as crucial for the transmembrane transport of STZ by microalgae. A plausible biotransformation pathway for STZ degradation was proposed, identifying hydroxylation, oxidation, ring cleavage, and formylation as the primary transformation processes. The up-regulation of key enzymes such as monooxygenases, dioxygenases, hydrolases, and transferases suggested their pivotal role in the biodegradation of STZ. This research provides valuable insights into the biotransformation mechanisms of STZ by microalgae, thereby laying a theoretical framework to advance the implementation of microalgae in the treatment of antibiotic-contaminated wastewater.

Photochemical Transformation of Ibuprofen and Chlorophene Induced by Dissolved Organic Matter.

Both ibuprofen (IBP) and chlorophene (CP) are frequently detected contaminants in surface aqueous environment. Dissolved organic matter (DOM) is an important component in water with high photo-reactivity, playing an important role in the transformation processes of various organic pollutants. This study systematically studied the influence of DOM on the photochemical transformation of IBP and CP by using humic acid as model DOM. In addition, the effect of inorganic salts on this process is also considered due to the high salt content in the ocean. Further quenching experiments and reactive oxygen species (ROSs) detection were also conducted to explore the reactive species acting on the IBP and CP transformation. Based on the products analysis and theoretical calculation, we proposed the IBP and CP transformation mechanism. Overall, this study provides some new insights into the transformation of organic pollutants in natural surface water, which is significant for assessing the fate of pollutants.

Deciphering the impact of cascade reservoirs on nitrogen transport and nitrate transformation: Insights from multiple isotope analysis and machine learning

Construction of cascade reservoirs has altered nutrient dynamics and biogeochemical cycles, thereby influencing the composition and productivity of river ecosystems. The Lancang River (LCR), characterized by its cascade reservoir system, presents uncertainties in nitrogen transport and nitrate transformation mechanisms. Herein, we conducted monthly monitoring of hydrochemistry and multiple stable isotopes (δ15N-NO3-, δ18O-NO3-, δ18O-H2O, δD-H2O) throughout 2019 in both the natural river reach (NRR) and cascade reservoirs reach (CRR) of the LCR. Through the monthly detection of nitrogen forms and runoff in the import (M2) and export (M9) section, the average annual retention ratios for Total nitrogen (TN), Nitrate nitrogen (NO3--N), Particulate Nitrogen (PN) and Ammonium Nitrogen (NH4+-N) were about -35%, -53%, 48% and -65%, respectively. The retention rates were positively correlated with hydraulic retention time and negatively correlated with reservoir age, especially in the flood season. Compared to the NRR, the reservoir had significantly affected the nitrogen transport characteristics, especially for the large reservoirs (like Xiaowan and Nuozhadu), which enhanced phytoplankton uptake of NO3--N to form PN capabilities in the lentic environment and subsequently to precipitate or intercept it at the reservoir. This led to the overall decreasing trend of TN and PN concentrations along the CRR. The Bayesian stable isotope model quantified NO3--N sources from the NRR to the CRR. During this transition, soil nitrogen (SN) ratios decreased from 69.3% to 61.8%, while Manure & sewage (M&S) increased from 24.0% to 31.3%. Anthropogenic and natural factors, including urban sewage discharge, population density, and precipitation, were selected as key predictor variables. The eXtreme Gradient Boosting (XGBoost) model exhibited superior predictive performance for NO3--N concentrations, achieving an R2 of 0.70. These findings deepen our understanding of the impact of reservoirs on river ecology.

Research on the Impact of Enterprise Digital Transformation on High-Quality Development and Countermeasures

With the rapid development of the digital economy, enterprises face the important task of digital transformation. This paper, based on the analysis of literature, discusses the positive impacts of digital transformation on the high-quality development of enterprises, reveals the main mechanisms of digital transformation, and proposes corresponding countermeasures for the challenges encountered by enterprises during the digital transformation process. The study finds that digital transformation can optimize the talent structure of enterprises, improve organizational governance, nurture new market environments, and thereby promote the high-quality development of enterprises. This paper suggests that enterprises should strengthen the training of digital talents, optimize organizational structures, and innovate business models using digital technologies to adapt to the needs of the digital age.

THE ROLE AND IMPACT OF VEGETATION ON THE URBAN FABRIC. CASE OF GUELMA CITY

In cities, land use changes caused by various human activities can affect how natural ecosystems function. In this context, it is increasingly important for cities to consider the role of vegetation in preserving a sustainable environment. A diachronic analysis of landscape changes was applied to assess the presence and distribution of vegetation to determine whether it was evolving or regressing. This phenomenon was studied within the current administrative boundaries of the city of Guelma (Algeria). For this purpose, as an approach based on landscape metrics, several Landsat TM and ETM+ remote sensing satellite images were used throughout the period 1987-2019. A set of landscape indices, including NP, AREA_MN, LPI, PLAND, AI and LSI, were calculated to map land cover, the mechanism of land cover and vegetation change, and their impact on the urban ecosystem. The geo-statistical procedure was carried out using a geographic information system Qgis combined by statistical software using Fragstats to calculate various landscape metrics at class level for the analysis of fragmentation . The results of the landscape metric analysis show that the decrease in average area and the increase in the number of green patches are important indicators of land degradation, meaning that the mechanism of landscape degradation and transformation is progressive. This underlines the need to give particular attention to land use and land cover in the region to ensure the sustainable allocation of natural resources.

AMTrack:Transformer tracking via action information and mix-frequency features

Nowadays, Transformer-based visual tracking algorithms have been developing quickly because of the self-attention mechanism of Transformer, which has the capability to model global information. Although the self-attention mechanism in Transformer can effectively capture long-range dependencies in feature space, they only use flattened two-dimensional features and are unable to capture long-range temporal dependencies. Furthermore, since the self-attention in Transformer functions as a low-pass filter, it picks up on low-frequency features of the target while ignoring high-frequency features. This research suggests a Transformer tracker based on action information and mix-frequency features (AMTrack) to address these problems. Specifically, to address the lack of temporal remote dependencies, we introduce the target action aware module and the target action offset module. The target action aware module sets up several pathways to extract spatio-temporal, channel, and motion feature independently. In contrast, the target action offset module computes the target’s offset information by computing relative feature maps. Furthermore, in order to address the imbalance between high and low frequency features, we propose a mix-frequency attention and multi-frequency self-attention convolutional block. The mix-frequency attention uses high-frequency features within partitioned local windows as input for the high-frequency branch and average-pooled low-frequency features as the input for the low-frequency branch, calculating attention scores in both branches respectively. The multi-frequency self-attention convolutional block uses self-attention to capture low-frequency features and convolution to capture high-frequency features. Extensive experiments are carried out on eight challenging tracking datasets (e.g., OTB100 (Object Tracking Benchmark 100), NFS (Need For Speed), UAV123 (Unmanned Aerial Vehicles 123), TC128 (Temple Color 128), VOT2018 (Visual Object Tracking 2018), LaSOT (Large-scale Single Object Tracking), TrackingNet (Tracking Network), GOT-10k (Generic Object Tracking-10k)), and the experimental results show that our tracker achieves excellent tracking performance when compared with several state-of-the-art tracking algorithms. The experimental results show that on LaSOT, the success rates AUC (Area Under Curve), PNorm, and P reach 65.8%, 69.2%, and 68.0%, respectively, where the AUC value is 2.1% higher than the baseline algorithm TrDiMP (Transformer Discriminative Model Prediction). On other datasets, our tracker also achieves excellent tracking performance.

Chromium cycle in Red Soil Critical Zone constrained by chromium isotopes

Chromium (Cr) isotopic system has been used to trace Cr pollution in the modern surface environment and redox change in the paleoenvironment. However, the transformation mechanism of Cr in soil and the accompanied Cr isotopic fractionation have not been clarified clearly. Here we measured Cr isotopic compositions (δ53Cr) of two paddy field profiles from the Red Soil Critical Zone Observatory in South China. The δ53Cr values of the young paddy fields, which have been cultivated for about 20 years, range from −0.34 ‰ to −0.22 ‰. The old paddy fields have been cultivated for >100 years and have more positive Cr isotopic compositions than the young paddy fields, from −0.20 ‰ to −0.06 ‰. The results of three-step leaching experiments show that iron and manganese oxides are enriched in heavy Cr isotopes, while organic matters have much lower Cr isotopic compositions, likely resulting from back reduction of Cr(VI). Our results suggest that Cr isotopic fractionation during the oxidation of Cr(III) is not the only reason for the depletion of heavy isotopes during oxidative weathering, and the partial back-reduction of generated Cr(VI) by organic matter plays an important role in Cr isotopic fractionation during weathering. Comparison between the old and young paddy fields further indicates that cultivation can significantly affect the Cr cycle in red soils. Paddy fields could be a potential sink for the Cr(VI) contaminant, and soils with a long history of cultivation would be more susceptible.