Cyclic Transformation Research Articles

Efficient Degradation of Ofloxacin by Magnetic CuFe2O4 Coupled PMS System: Optimization, Degradation Pathways and Toxicity Evaluation.

Magnetic CuFe2O4 was prepared with the modified sol-gel method and used for enhanced peroxymonosulfate (PMS) activation and ofloxacin (OFL) degradation. The OFL could almost degrade within 30 min at a catalyst dosage of 0.66 g/L, PMS concentration of 0.38 mM, and initial pH of 6.53 without adjustment, using response surface methodology (RSM) with Box-Behnken design (BBD). In the CuFe2O4/PMS system, the coexisting substances, including CO32-, NO3-, SO42-, Cl- and humic acid, have little effect on the OFL degradation. The system also performs well in actual water, such as tap water and surface water (Mei Lake), indicating the excellent anti-interference ability of the system. The cyclic transformation between Cu(II)/Cu(I) and Fe(III)/Fe(II) triggers the generation of active radicals including SO4•-, •OH, •O2- and 1O2. The OFL degradation pathway, mainly involving the dehydrogenation, deamination, hydroxylation, decarboxylation and carboxylation processes, was proposed using mass spectroscopy. Moreover, the toxicity assessment indicated that the end intermediates are environmentally friendly. This study is about how the CuFe2O4/PMS system performs well in PMS activation for refractory organic matter removal in wastewater.

A contour integral-based method for nonlinear eigenvalue problems for semi-infinite photonic crystals

In this study, we introduce an efficient method for determining isolated singular points of two-dimensional semi-infinite and bi-infinite photonic crystals, equipped with perfect electric conductor and quasi-periodic mixed boundary conditions. This specific problem can be modeled by a Helmholtz equation and is recast as a generalized eigenvalue problem involving an infinite-dimensional block quasi-Toeplitz matrix. Through an intelligent implementation of cyclic structure-preserving matrix transformations, the contour integral method is elegantly employed to calculate the isolated eigenvalue and to extract a component of the associated eigenvector. Moreover, a propagation formula for electromagnetic fields is derived. This formulation enables rapid computation of field distributions across the expansive semi-infinite and bi-infinite domains, thus highlighting the attributes of edge states. The preliminary MATLAB implementation is available at https://github.com/FAME-GPU/2D_Semi-infinite_PhC.

Cyclic Consistent Image Style Transformation: From Model to System

Cyclic Consistent Image Style Transformation: From Model to System

Activation of Peroxodisulfate Coupled with Photocatalysis by Pyrrolic N‐Rich Fe‐N4 Sites for High Efficiency Degradation of Tetracycline Hydrochloride

AbstractPhotocatalysis is an efficient technology for the degradation of pollutants. However, there is still much room for improvement in its degradation efficiency. In this study, a pyrrolic N‐rich g‐C3N4 (PN‐g‐C3N4) framework was synthesized with transition metal M (M=Fe, Co, Ni, Cu, Cr, and Mn) atomic sites coordinated onto it. Then, a series of single atomic metals M anchored to PN‐g‐C3N4 (M/PN‐g‐C3N4) are constructed for peroxodisulfate activation. Their order of catalytic activity follows Fe>Cr>Ni>Cu≈Co>Mn, in particular the degradation rates of the TCH for Fe‐PN‐g‐C3N4 are 3.74 times higher than that of undoped PN‐g‐C3N4. These carefully regulated pyrrolic N‐rich Fe sites demonstrate outstanding performance in degrading organic pollutant. As an exemplary model, the Fe/PN‐g‐C3N4 catalyst efficiently drives the catalytic oxidation of TCH through Fenton‐like reaction under visible light, showcasing exceptional cycle stability and a broad effective pH range of 3.0–11.0. The synergy between photocatalysis and Fe doped catalysis results in increased generation and separation of charge carriers, along with the cyclic transformation of the Fe3+/Fe2+ couple. This combination significantly enhances the Fenton‐like performance, making it a highly effective process for pollutant degradation.

Talbot-like pattern evolution in complex structured light from a unitary transformation

Astigmatic unitary transformations allow for the adiabatic connections of all feasible states of paraxial Gaussian beams on the same modal sphere, i.e., Hermite-Laguerre-Gaussian (HLG) modes. Here, we present a comprehensive investigation into the unitary modal evolution of complex structured Gaussian beams, comprised of HLG modes from disparate modal spheres, via astigmatic transformation. The non-synchronized higher-order geometric phases in cyclic transformations originate a Talbot-effect-like modal evolution in the superposition state of these HLG modes, resulting in pattern variations and revivals in transformations with specific geodesic loops. Using Ince-Gaussian modes as an illustrative example, we systematically analyze and experimentally corroborate the beamforming mechanism behind the pattern evolution. Our results outline a generic modal conversion theory of structured Gaussian beams via astigmatic unitary transformation, offering a new approach for shaping spatial modal structure. These findings may inspire a wide variety of applications based on structured light.

Estimate of the time required to perform a nonadiabatic holonomic quantum computation

Nonadiabatic holonomic quantum computation has been proposed as a method to implement quantum logic gates with robustness comparable to that of adiabatic holonomic gates but with shorter execution times. In this paper, we establish an isoholonomic inequality for quantum gates, which provides a lower bound on the lengths of cyclic transformations of the computational space that generate a specific gate. Then, as a corollary, we derive a nonadiabatic execution time estimate for holonomic gates. In addition, we demonstrate that under certain dimensional conditions, the isoholonomic inequality is tight in the sense that every gate on the computational space can be implemented holonomically and unitarily in a time-optimal way. We illustrate the results by showing that the procedures for implementing a universal set of holonomic gates proposed in a pioneering paper on nonadiabatic holonomic quantum computation saturate the isoholonomic inequality and are thus time optimal. Published by the American Physical Society 2024

Crucial roles of soil inherent Fe-bearing minerals in enhanced Cr(VI) reduction by biochar: The electronegativity neutralization and electron transfer mediation

Biochar has been used for soil Cr(VI) remediation in the last decade due to its enriched redox functional groups and good electrochemical properties. However, the role of soil inherent Fe-bearing minerals during the reduction of Cr(VI) has been largely overlooked. In this study, biochar with different electron-donating capacities (EDCs) was produced at 400 °C (BC400) and 700 °C (BC700), and their performance for Cr(VI) reduction in soils with varied properties (e.g., Fe content) was investigated. The addition of BC400 caused around 14.2–36.0 mg g−1 Cr(VI) reduction after two weeks of incubation in red soil, paddy soil, loess soil, and fluvo-aquic soil, while a less Cr(VI) was reduced by BC700 (2.57–16.7 mg g−1) with smaller EDCs. The Cr(VI) reduction by both biochars in different soils was closely related to Fe content (R2 = 0.93–0.98), so red soil with the richest Fe (14.8% > 1.79–3.49%) showed the best reduction capability, and the removal of soil free Fe oxides (e.g., hematite) resulted in 71.9% decrease of Cr(VI) reduction by BC400. On one hand, Fe-bearing minerals could increase the soil acidity, neutralize the surface negative charge of biochar, enhance the contact between Cr(VI) and biochar, and thus facilitate the direct Cr(VI) reduction by biochar in soils. On the other hand, Fe-bearing minerals could also facilitate the indirect Cr(VI) reduction by mediating the electron from biochar to Cr(VI) with the cyclic transformation of Fe(II)/Fe(III). This study demonstrates the key role of soil Fe-bearing minerals in Cr(VI) reduction by biochar, which advances our understanding on the biochar-based remediation mechanism of Cr(VI)-contaminated soils.

A quantum moving target segmentation algorithm for grayscale video based on background difference method

The classical moving target segmentation (MTS) algorithm in a video can segment the moving targets out by calculating frame by frame, but the algorithm encounters a real-time problem as the data increases. Recently, the benefits of quantum computing in video processing have been demonstrated, but it is still scarce for MTS. In this paper, a quantum moving target segmentation algorithm for grayscale video based on background difference method is proposed, which can simultaneously model the background of all frames and perform background difference to segment the moving targets. In addition, a feasible quantum subtractor is designed to perform the background difference operation. Then, several quantum units, including quantum cyclic shift transformation, quantum background modeling, quantum background difference, and quantum binarization, are designed in detail to establish the complete quantum circuit. For a video containing 2m\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$2^{m}$\\end{document} frames (every frame is a 2n×2n\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$2^{n} \ imes 2^{n}$\\end{document} image with q grayscale levels), the complexity of our algorithm is O(n+q)\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$(n+q)$\\end{document}. This is an exponential speedup over the classical algorithm and also outperforms the existing quantum algorithms. Finally, the experiment on IBM Q demonstrates the feasibility of our algorithm in this noisy intermediate-scale quantum (NISQ) era.

Deterministic engines extending Helmholtz thermodynamics

Helmholtz formalism provides a tantalizing interpretation of classical thermodynamics, based on time integrals of purely mechanical quantities and without need of statistical description. Here we extend this approach to include heat flux and pressure at the walls to enable it to describe actual thermodynamic transformations, such as isothermal compressions and expansions. The presence of hard walls, which gives rise to non zero pressure, is justified by means of the virial theorem, while the heat fluxes are introduced as quasi-static limits of suitably thermostatted Hamiltonians. Particular attention is paid to generalizing the minimalist cases of the harmonic oscillator and elastic bouncer, which afford clear physical interpretations. With such extensions, a complete picture of thermodynamics emerges, amenable to phase transitions and cyclic deterministic transformations, which produce mechanical work from heat, like the Carnot cycle.

Power-efficient programmable integrated multiport photonic interferometer in CMOS-compatible silicon nitride

Silicon nitride (SiN x ) is an appealing waveguide material choice for large-scale, high-performance photonic integrated circuits (PICs) due to its low optical loss. However, SiN x PICs require high electric power to realize optical reconfiguration via the weak thermo-optic effect, which limits their scalability in terms of device density and chip power dissipation. We report a 6-mode programmable interferometer PIC operating at the wavelength of 1550 nm on a CMOS-compatible low-temperature inductance coupled plasma chemical vapor deposition (ICP-CVD) silicon nitride platform. By employing suspended thermo-optic phase shifters, the PIC achieves 2× improvement in compactness and 10× enhancement in power efficiency compared to conventional devices. Reconfigurable 6-dimensional linear transformations are demonstrated including cyclic transformations and arbitrary unitary matrices. This work demonstrates the feasibility of fabricating power-efficient large-scale reconfigurable PICs on the low-temperature ICP-CVD silicon nitride platform.

Effect of cobalt addition on thermal cycling behaviour of Ti50Ni(50−x)cox shape memory alloys

The effect of adding Co on the temperature cycling behaviour of ternary Ti50Ni(50−x)Cox (x = 1, 2, 3) alloys was experimentally studied in this work. The alloys were prepared using a vacuum induction furnace, followed by subjecting them to homogenization, hot-rolling and annealing processes. The alloys were subjected to thermal cycling experiments in a nitrogen atmosphere by differential scanning calorimetry under stress-free conditions between their transformation temperatures. The results indicate that adding Co to NiTi alloys decreases their transition temperatures, improves the thermal cycling stability apart from suppressing the R-phase formation on cooling during cycling. The changes are due to the addition of Co introducing solid solution strengthening and generation of dislocations during cyclic phase transformations, as confirmed by the hardness test results and TEM micrographs, respectively.

Effect of Temperature on the Cyclic Fatigue Resistance and Phase Transformation Behavior of Three Different NiTi Endodontic Instruments.

Background This study aims to analyze the phase transformation behavior and evaluate the effect of different temperatures on the fracture strength of files. Methodology A total of 108 files were used, and cyclic fatigue tests were performed on HyFlex EDM, VDW.ROTATE, and TruNatomy at three different temperatures (+4°C, +35°C, and +60°C) The time to fracture of files was measured, and the number of cycles was calculated. In addition, the fractured fragment lengths were measured. The Kruskal-Wallis test was used to compare the data that were not normally distributed according to groups. The Mann-Whitney U test was performed for comparisons. P-values <0.05 were considered statistically significant. Results As the temperature increased for all files, the number of cycles to fracture (NCF) decreased. NCF was significantly higher for ROTATE at 4°C and 60°C and HyFlex EDM at 35°C. Conclusions The resistance to cyclic fatigue in all files decreased significantly as the temperature increased.

Nanocrystals Conversion Chemistry within Slit-like 2D-Nanogap for High-Rate Cyclic Stability of Lithium-Ion Battery Anodes

A deep understanding of nanocrystal (NC) conversion chemistry is necessary to access alternative synthetic routes for naturally inaccessible nanostructures and fundamental solutions of any interference impeding their practical applications. For durable catalytic processes and practical energy storage devices, this can enable sustaining full reversibility connecting the active NC components under long, harsh operational conditions. Redox convertible late transition metal oxide (TMO) NCs are excellent anode materials for Li-ion batteries (LIBs) with many superior properties but have deviated from the reversible lithiation/delithiation mechanism (MxOy + 2yLi+ + 2e- xM0/yLi2O). Thus, undesired NC-coalescence and irreversible solid-electrolyte-interphase (SEI) formations result in significant capacity loss with repeated charge/discharge cycles and at high cycling rates (>2.0 C). Several methods, involving immobilization on conductive supports, manipulated crystalline phases, and fabricating hierarchical assemblies, have been investigated to resolve this issue. Sheet-like 2D-TMO nanostructures, which electrochemically convert to reduced metal NC-arrays in 2D-geometry, have proven effective at improving reversible and cycling anode performance at moderate current density ranges (0.2 ~ 1.0 C). However, for practical LIB devices, an increased storage performance, especially at quick charging conditions (> 3.0 C), is required, which may be realized through optimizing 2D-TMOs for improved conversion reversibility. However, as the attempted 2D-TMOs have rough thickness uniformity mostly in the 10 ~ 100 nm range long with the lateral size above 250 nm and often fabricated in the carbon-hybrid form, precise interpretation of thickness-dependent effects of 2D-TMO electrodes, especially within a few-nm-thick range, is still unaccomplished. Hence, we attempted fabrication of thinner 2D-TMOs with well-controlled uniform few-nm thicknesses and assess their effectiveness as LIB anodes based on transformation behavior under redox-switching conditions. The confinement of in-situ created NCs inside the few-nm-thin 2D-nanospace, as pre-defined by the thickness of initial 2D-TMO, would hinder free movement, agglomeration, and sintering of included NCs during their phase transition, improving conversion reversibility. The use of atomic-thin 2D-TMOs was envisioned to place single laterally aligned NC arrays at the ultrathin 2D nanogap, ensuring fully reversible interconversion between reactive NC redox-pairs. However, atomic-thin 2D nanosheets of late TMOs, which are intrinsically non-layered materials, remain a synthetic challenge under conventional methods.Herein, we adopted the nanospace confinement strategy to thermally transform delaminated layered double hydroxides (NiCo-LDH) within a 2D-SiO2 envelope, forming isomorphic 2D-TMOs (Ni3Co1Ox, NCOs) of uniform 1 nm and 7 nm thicknesses from LDH precursors. A thermal conversion study of the 2D-TMOs under the 2D-SiO2-shell protection, as well as an electrochemical investigation within the in-situ formed 2D SEI-envelope identified a substantial confinement effect on sustaining the fully cyclic transformation behavior of the derived NC arrays from 1 nm-thin 2D-TMOs. Thus, the atomic-thin 2D-TMO anode demonstrated highly reversible capacity of 848.36 mAh g-1 at the first cycle and a high-rate capability (a specific capacity of 61.2% at 5.0 C relative to 0.2 C) and, the long-term stable Li-ion storage capacity delivered 1169 mAh g-1 and 913 mAh g-1 of specific capacity during 1000 cycles even at rapid charge/discharge conditions of 3.0 C and 5.0 C rates, respectively.

Vertically Resolved Global Ocean Light Models Using Machine Learning

The vertical distribution of light and its spectral composition are critical factors influencing numerous physical, chemical, and biological processes within the oceanic water column. In this study, we present vertically resolved models of downwelling irradiance (ED) at three different wavelengths and photosynthetically available radiation (PAR) on a global scale. These models rely on the SOCA (Satellite Ocean Color merged with Argo data to infer bio-optical properties to depth) methodology, which is based on an artificial neural network (ANN). The new light models are trained with light profiles (ED/PAR) acquired from BioGeoChemical-Argo (BGC-Argo) floats. The model inputs consist of surface ocean color radiometry data (i.e., Rrs, PAR, and kd(490)) derived by satellite and extracted from the GlobColour database, temperature and salinity profiles originating from BGC-Argo, as well as temporal components (day of the year and local time in cyclic transformation). The model outputs correspond to ED profiles at the three wavelengths of the BGC-Argo measurements (i.e., 380, 412, and 490 nm) and PAR profiles. We assessed the retrieval of light profiles by these light models using three different datasets: BGC-Argo profiles that were not used for the training (i.e., 20% of the initial database); data from four independent BGC-Argo floats that were used neither for the training nor for the 20% validation dataset; and the SeaBASS database (in situ data collected from various oceanic cruises). The light models show satisfactory predictions when thus compared with real measurements. From the 20% validation database, the light models retrieve light variables with high accuracies (root mean squared error (RMSE)) of 76.42 μmol quanta m−2 s−1 for PAR and 0.04, 0.08, and 0.09 W m−2 nm−1 for ED380, ED412, and ED490, respectively. This corresponds to a median absolute percent error (MAPE) that ranges from 37% for ED490 and PAR to 39% for ED380 and ED412. The estimated accuracy metrics across these three validation datasets are consistent and demonstrate the robustness and suitability of these light models for diverse global ocean applications.

Anisotropy reduction and mechanical property improvement of additively manufactured stainless steel based on cyclic phase transformation

Owing to the special layer-by-layer deposition process of directed energy deposition (DED), columnar coarse grains, produced by cyclic reheating with intrinsic directional heat flow along the building direction, are difficult to avoid. These grains result in strong anisotropic characteristics with poor mechanical properties, which restrict the application of DED products. This work proposes a novel fabrication strategy based on the cyclic-phase-transformation behavior, which can reduce the anisotropy and improve the mechanical properties of DED-printed stainless steel. Using this fabrication strategy, 316 L powder (austenitic stainless steel) and 17–4PH powder (martensitic stainless steel) were mixed in different mass ratios to fabricate five types of DED-printed stainless steels. Among the five samples, P70 (mixture of 70 wt% 17–4PH powder and 30 wt% 316 L powder) showed the weakest anisotropy and the best mechanical properties, which can be attributed to the cyclic phase transformation under cyclic reheating treatment and the transformation-induced plasticity (TRIP) effect over a wide range of strains, respectively. Compared with the pure 316 L printed material, the tensile test results of P70 showed that the yield strength (YS) and ultimate tensile strength (UTS) increased by 35.4% and 34.5%, respectively, whereas the uniform elongation (UE) and total elongation (TE) were improved by 63.9% and 31.4%, respectively. In addition, the strength–ductility balance (UTS × UE) increased by as much as 120.4%. The proposed fabrication strategy is expected to reduce the anisotropy in other materials that undergo cyclic-phase-transformation phenomena during additive manufacturing.

Computationally efficient simulation methodology for railway repair welding: Cyclic plasticity, phase transformations and multi-phase homogenization

The in-situ railway repair welding process consists of multiple weld passes, which makes it significantly different from other rail welding processes. In this study, finite element simulations of repair welding are performed to predict the resulting microstructure and residual stresses. To accurately simulate the material behavior, the modeling includes phase transformation kinetics, cyclic hardening plasticity, transformation induced plasticity, and multi-phase homogenization. More specifically, four different homogenization methods are investigated: isostrain, isostress, self-consistent and linear mixture rule. The performance of the material modeling is demonstrated by simulating multiple weld passes using a classical three-bar welding experiment. Based on the results, the self-consistent method and linear mixture rule are used in a 3D full-scale railhead repair weld simulation, in which the former generates a more realistic mechanical response. The immense computational cost associated with 3D full-scale, full-detail multi-pass welding simulations is addressed by exploring different model reduction schemes. From this study, a 2D generalized plane strain model, extended with out-of-plane axial and bending stiffness, is found to replicate the full-scale model at a mere fraction of the computational cost. Finally, the longitudinal residual stress distribution obtained from the reduced model is shown to correlate well with experimental measurements.

Classification and Simulation of Structural Phase Transformation-Induced Interfacial Defects in Group VI Transition-Metal Dichalcogenide Monolayers.

Polymorphic 2D materials have recently emerged as promising candidates for use in nanoelectronic devices by way of their ability to undergo structural phase transformations induced by external fields. Under cyclic transformations, however, induced interfacial defects may proliferate and compromise the system properties. Herein, we first employ geometric analysis to classify such defects generated during the 2H ↔ 1T and 2H ↔ 1T' transformations in group VI transition-metal dichalcogenide monolayers. Then, simulations of a mesoscale model with atomistic spatial resolution are conducted to assess the proliferation of such defects during cyclic 2H ↔ 1T transformations. It is shown that defect densities reach a steady state, with the 2H phase remaining more pristine than the 1T and 1T' states. We expect that the effects of these defects on the device performance are application-dependent and will require further inquiry.

Effective Thermoelectric Switch of Hollow Weakly-Coupled Molecular Junction Based on Twist Angle Effect with Boron-Doping

ABSTRACT Rational design and adjustment of flexible thermoelectric devices are key points for sustainable and effective thermoelectric conversion, which remains a fundamental challenge due to inherent high thermal conductivity and uncontrolled carrier concentration induced by non-uniform dispersion. Under ingenious combination of weakly-coupled hollow interface and nanotube structure, thermoelectric performance of a dumbbell-like molecular junction comprised of a phenyl-terminated polyyne as central molecule and two semi-infinite 1D single-walled carbon nanotube (SWCNT) as electrodes has been investigated at certain twisted angles (θ). The results indicate that molecule twisting can be reviewed as an effective thermoelectric switch to coordinatingly control electronic and phononic transmission properties simultaneously. Resonance of molecular discrete state and electrode continuous state leads to low thermal conductance, which is sensitively affected by twist angle. Meanwhile, cyclic transformation between p-type and n-type flexible thermoelectrics can be realized by manipulating twist angle in a certain period of rotation. Thermoelectric performance of such a molecular junction can be further improved by boron atom doping at head-to-tail positions, and an excellent figure of merit (ZT = 1.75) is observed near Fermi level under 25° twisted angle. This result inspires an effective strategy to modulate and control thermoelectric conversion, which will greatly broaden applications in thermoelectric twistronics.

Cause Analysis of Condensed Water Induced Bulging in High-Pressure Steam Tee Joints of a Pyrolyzer

High-pressure steam pipes inevitably suffered from the reciprocal interaction of high pressure and temperature during a long-period service, causing deformation and cracking. However, only limited studies about abnormal bulging caused by condensed water have been carried out. To study the relationship between bulging and condensed water, bulging tee joints belonging to high-pressure steam pipes were investigated with a macro visual inspection, chemical composition analysis, and metallographic microscopy. According to the analysis of the bulging samples, pearlite spheroidization was found in the abnormal bulging tee joint. The ANSYS FLUENT modeling indicated that the tube wall of bulging tees was continuously subjected to alternating stress, causing the cyclic transformation of the liquid–gas phase inside the tee joint. The results indicate that the stress produced by a condensed water droplet ranges from 532.8 MPa to 59 MPa, continuously exerting pressure on the tube wall of the tee joint. When combined with the variation in the temperature field, the temperature of the severe bulging tee joint and slight bulging tee joint alternates. Further modeling illustrates that the stress generated by the impact of condensed water droplets on the high-temperature tee joints causes a ratcheting effect, which is identified as the main factor contributing to the bulging of the tee joint. Deterioration of the microstructure is considered a secondary mechanism.

Particles attrition of binary mixtures in the coal-fueled chemical looping system based on fluidized bed

In this work, a reactive air jet attrition device with auto-recording and collection of elutriated fines was developed. Results established insights into the physiochemical interaction and further correlated attrition behaviors between char and oxygen carriers under various operation modes. The attrition rate increased by over 110% upon the introduced CO2, which brought in the significant effect of thermochemical stress, similarly in effects of the increased char addition ratio and the decreased sizes of char or hematite in different extents. For the char-hematite co-attrition process, the elutriated carbon loss of char with poor mechanical strength was found to be over 10%, while the reactive iron loss of hematite was found to be 6.3%, and was enriched in elutriated fines. The reaction-derived thermochemical stress and the collision-derived mechanical stress jointly controls the particle attrition during the cyclic transformation of oxygen carrier particles in coal-fueled chemical looping fluidization, especially significant in its reduction stage.