Transition Mechanism Research Articles

Shedding light on blue-green photosynthesis: A wavelength-dependent mathematical model of photosynthesis in Synechocystis sp. PCC 6803.

Cyanobacteria hold great potential to revolutionize conventional industries and farming practices with their light-driven chemical production. To fully exploit their photosynthetic capacity and enhance product yield, it is crucial to investigate their intricate interplay with the environment including the light intensity and spectrum. Mathematical models provide valuable insights for optimizing strategies in this pursuit. In this study, we present an ordinary differential equation-based model for the cyanobacterium Synechocystis sp. PCC 6803 to assess its performance under various light sources, including monochromatic light. Our model can reproduce a variety of physiologically measured quantities, e.g. experimentally reported partitioning of electrons through four main pathways, O2 evolution, and the rate of carbon fixation for ambient and saturated CO2. By capturing the interactions between different components of a photosynthetic system, our model helps in understanding the underlying mechanisms driving system behavior. Our model qualitatively reproduces fluorescence emitted under various light regimes, replicating Pulse-amplitude modulation (PAM) fluorometry experiments with saturating pulses. Using our model, we test four hypothesized mechanisms of cyanobacterial state transitions for ensemble of parameter sets and found no physiological benefit of a model assuming phycobilisome detachment. Moreover, we evaluate metabolic control for biotechnological production under diverse light colors and irradiances. We suggest gene targets for overexpression under different illuminations to increase the yield. By offering a comprehensive computational model of cyanobacterial photosynthesis, our work enhances the basic understanding of light-dependent cyanobacterial behavior and sets the first wavelength-dependent framework to systematically test their producing capacity for biocatalysis.

Extrachromosomal circular DNA-related SPOCK1 contributes to development and enzalutamide resistance of prostate cancer by regulating epithelial mesenchymal transition

Prostate cancer is a significant contributor to cancer-related mortality, and the tumor typically develops into castration-resistant prostate cancer (CRPC). Hence, few effective clinical strategies are available to patients with advanced disease. Extrachromosomal circular DNA (eccDNA) is a type of circular DNA originating from the chromosomes but is likely independent of them. Because of its unique structural characteristics, eccDNA has extensive applications as a new biomarker for cancer prevention and treatment. Circle-seq obtains a comprehensive picture of the overall landscape of eccDNA sizes and content in cell populations. In this study, we used Circle-seq and studied the distribution pattern and expression level of eccDNA in prostate cancer. We confirmed that eccDNA is derived from every human chromosome and has sequences from all known types of genomic structures, revealing it is a common mutational element in prostate cancer. We also identified an eccDNA-related gene SPOCK1 that promotes drug resistance, proliferation, and metastasis of many cancers through the epithelial-mesenchymal transition (EMT) mechanism. The SPOCK1-associated eccDNA was highly upregulated in various groups of sequencing results, and SPOCK1 was highly expressed in prostate cancer tissues and cells. Therefore, SPOCK1 exists as eccDNA in prostate cancer and encourages its development and drug resistance via the EMT mechanism. Our results suggest that upregulated genes in the form of eccDNA are oncogenes in prostate cancer and play a pivotal role in carcinogenesis.

Adapting to climate change and the European Union pursuit of a just transition

The European Green Deal was launched by the European Commission (EC) in December 2019, before being formally approved in 2020. It comprises a package of policy measures that aim to set the European Union (EU) on the path to a green transition, with the ultimate objective of achieving climate neutrality by 2050. Despite the EU’s longstanding commitment to reducing carbon emissions in support of climate change mitigation and the achievement of its net zero ambition, this paper focuses on the growing importance of climate change adaptation within its policy portfolio. With respect to the latter, the long-term vision is for the EU to become a climate-resilient society that is also fully adapted to the unavoidable impacts of climate change. Achieving climate neutrality and a climate-resilient society by 2050 will be more challenging for some EU member states and regions than for others, eg poorer regions and those highly dependent on fossil fuels or with carbon-intensive industries that employ significant numbers of people. To address such issues, the EU has introduced a Just Transition Mechanism to help level the playing field and provide financial and technical support to regions most adversely affected by the move towards a low carbon economy. The paper traces the evolution of the EU’s climate policy agenda leading up to the adoption of the Green Deal, outlines its proposed road map in pursuit of climate neutrality and a climate-resilient society by 2050, and questions the efficacy of some its intermediate targets including the adequacy and equity of its just transition aspirations. It also details and scrutinises the key role that the European Investment Bank (EIB) will play in supporting delivery of the strategy.1,2

Adapting to climate change and the European Union pursuit of a just transition

The European Green Deal was launched by the European Commission (EC) in December 2019, before being formally approved in 2020. It comprises a package of policy measures that aim to set the European Union (EU) on the path to a green transition, with the ultimate objective of achieving climate neutrality by 2050. Despite the EU’s longstanding commitment to reducing carbon emissions in support of climate change mitigation and the achievement of its net zero ambition, this paper focuses on the growing importance of climate change adaptation within its policy portfolio. With respect to the latter, the long-term vision is for the EU to become a climate-resilient society that is also fully adapted to the unavoidable impacts of climate change. Achieving climate neutrality and a climate-resilient society by 2050 will be more challenging for some EU member states and regions than for others, eg poorer regions and those highly dependent on fossil fuels or with carbon-intensive industries that employ significant numbers of people. To address such issues, the EU has introduced a Just Transition Mechanism to help level the playing field and provide financial and technical support to regions most adversely affected by the move towards a low carbon economy. The paper traces the evolution of the EU’s climate policy agenda leading up to the adoption of the Green Deal, outlines its proposed road map in pursuit of climate neutrality and a climate-resilient society by 2050, and questions the efficacy of some its intermediate targets including the adequacy and equity of its just transition aspirations. It also details and scrutinises the key role that the European Investment Bank (EIB) will play in supporting delivery of the strategy.1,2

Thermo-sensitive poly(amino acid) hydrogel mediates cytoprotection through an antioxidant mechanism

Oxidative stress, characterized by the excessive accumulation of reactive oxygen species (ROS), is linked to various pathological conditions, including myocardial infarction, cancer, and neurodegenerative diseases. Addressing ROS-induced cell damage has become a critical focus of biomedical research. In this study, a thermo-sensitive poly(amino acid) hydrogel, composed of poly(ethylene glycol)-block-poly(L-methionine), was prepared for cytoprotection through ROS scavenging. The sol-to-gel transition mechanism of the hydrogel was elucidated, and its potent antioxidant properties and cell protective effects were validated using hydrogen peroxide (H2O2)-induced oxidative stress and oxygen-glucose deprivation (OGD) models. The hydrogel significantly mitigated H2O2-induced damage in L929 cells, doubling their survival rate. Additionally, it scavenged approximately 35.8% of the ROS during OGD, reducing mitochondrial oxidative damage and resulting in a 29.4% decrease in apoptotic cell numbers. These findings underscore the potential biomedical applications of thermo-sensitive poly(amino acid) hydrogels, particularly in treating oxidative stress-related cell damage.

The cation exchange driving multi-phase regulation in Co7Fe3/Co@NC for enhanced broadband electromagnetic wave absorption

Phase engineering offers distinctive advantages in designing efficient electromagnetic wave (EMW) absorbers. The manipulation of the interaction and arrangement of different multi-phase systems enables the achievement of more precise EMW absorption. However, the transition mechanism from single metal phases to metal/alloy phases has not yet been fully revealed. Here, we employ multiphase engineering driven by cation exchange reactions to finely control the proportion of Co/Co7Fe3 phases and regulate electromagnetic parameters. The introduction of cavities and heteroatoms through cation exchange enables optimized defect distribution and composition, which enhances both impedance matching and electromagnetic attenuation capabilities. Specifically, we yield hollow Co7Fe3/Co@N-doped carbon (H-Co7Fe3/Co@NC) embedded in high-crystallinity graphite carbon after high-temperature pyrolysis, which promotes significant electron transfer between phases, thus enhancing conduction and polarization losses. H-Co7Fe3/Co@NC exhibits ultra-strong reflection loss (RL) of −59.70 dB at 9.37 GHz and achieves broadband absorption of 6.01 GHz at 2.1 mm. This study highlights the influence of Co7Fe3/Co heterogeneous structures on absorption performance and validates the electromagnetic response mechanism of multi-phase heterostructures through COMSOL finite element simulation analysis. Thus, this work paves the way for applying multi-phase engineering driven by cation exchange reactions for advanced absorbers.

Brittle-ductile transition mechanism during grinding 4H-SiC wafer considering laminated structure

4H-SiC wafer with alloy backside layer is gradually applied in power devices. However, the laminated structure presents various challenges in manufacturing. In this study, a model for brittle-ductile transition in grinding of laminated materials is established and verified by grinding experiment to ensure the complete removal of the alloy backside layer while achieving ductile removal of the 4H-SiC layer. In the modeling process, the maximum unreformed chip thickness and brittle-ductile transition critical depth of each-layer in the laminated material is deriving, taking into account the laminated structure. Consider the variability in proportion of dynamic active grits during grinding, set operation is introduced to analyze the relationship between sets maximum unreformed chip thickness and brittle-ductile transition critical depth, and to predict the removal mechanism of the 4H-SiC layer. Comparing the predicted results with experimental grinding data, found that under the conditions of grinding wheel with average size of abrasive 10 μm, grinding wheel speed vs of 74 m/s, grinding depth ap of 10 μm, and feeding speed vw of 2 mm/s, the alloy backside layer can complete removal while achieving ductile removal of the 4H-SiC layer. This study provides a new method for predicting removal mechanism in grinding of laminated material and theoretical guidance for optimizing machining parameters of 4H-SiC wafer with alloy backside layer.

Diffuse scattering from dynamically compressed single-crystal zirconium following the pressure-induced α→ω phase transition

The prototypical α→ω phase transition in zirconium is an ideal test bed for our understanding of polymorphism under extreme loading conditions. After half a century of study, a consensus had emerged that the transition is realized via one of two distinct displacive mechanisms, depending on the nature of the compression path. However, recent dynamic-compression experiments equipped with diffraction diagnostics performed in the past few years have revealed new transition mechanisms, demonstrating that our understanding of the underlying atomistic dynamics and transition kinetics is in fact far from complete. We present classical molecular dynamics simulations of the α→ω phase transition in single-crystal zirconium shock compressed along the [0001] axis using a machine-learning-class potential. The transition is predicted to proceed primarily via a modified version of the two-stage Usikov-Zilberstein mechanism, whereby the high-pressure ω phase heterogeneously nucleates at boundaries between grains of an intermediate β phase. We further observe the fomentation of atomistic disorder at the junctions between β grains, leading to the formation of highly defective interstitial material between the ω grains. We directly compare synthetic x-ray diffraction patterns generated from our simulations with those obtained using femtosecond diffraction in recent dynamic-compression experiments, and show that the simulations produce the same unique, anisotropic diffuse scattering signal unlike any previously seen from an elemental metal. Our simulations suggest that the diffuse signal arises from a combination of thermal diffuse scattering, nanoparticlelike scattering from residual kinetically stabilized α and β grains, and scattering from interstitial defective structures. Published by the American Physical Society 2024

Optimized Collective Variable for Collapse Transition in Linear Hydrophobic Polymers: Importance of Hydration Water and End-to-End Distance.

Choosing an appropriate collective variable (CV) for any biomolecular process is a challenging task. Researchers are developing methods to solve this issue using a variety of methodologies, most recently using machine learning (ML) methods. In this work, we investigate the mechanism of collapse transition across various lengths of polymer systems through adaptively sampled multiple short trajectories utilizing the Time Lagged Independent Component Analysis (TICA) framework. From TICA analysis, it is revealed that the radius of gyration (Rg) and end-to-end distance serve as good order parameters (OPs) for these systems describing overall energy landscapes. Markov state model (MSM) and mean first passage time (MFPT) analysis suggest that hydration water (Nw) plays a determining role in dictating the time scale and barrier for the collapsed transition for the C40 system. P-fold analysis on identifying transition state ensembles (TSE) identified by committor analysis also strengthens the role of Nw in such a transition. TICA, MSM, and committor analyses on the collapse transition for C45 reveal similarities with C40 systems in different aspects. Furthermore, we propose a pipeline integrating XGBoost regression along with an interpretable ML model, Shapley Additive exPlanation (SHAP) to precisely elucidate the contribution of each OP locally at the TSE. Through this approach, we observe that the collapse transition is primarily driven by Nw for both polymer systems. A carefully designed protocol for the collapsed transition of C60 systems indirectly reiterates the above result. Overall, our results suggest that while the end-to-end distance should be considered for better resolution of metastable states in the landscape, Nw is the crucial coordinate to be used in enhanced sampling for the exploration of actual collapse transitions for linear hydrophobic polymer systems. The Python code for analyzing the contribution of different OPs in the TSE using an ML-aided protocol is available on GitHub (https://github.com/saikat-ai/linear_polymer_project).

The structural mechanisms of pressure-induced phase transitions in the Carpy-Galy phase layered perovskites

In layered perovskites with the Carpy-Galy structural type, similar structural phase transitions occur under high pressure. These structural changes, which are crucial for the pressure-induced phase transition in layered perovskite, were analyzed based on experimental X-ray diffraction data. The tilting of the Ti-O6 octahedra and the distortion of the arrangement of rare-earth atoms were studied in detail. Changes in these structural features in layered perovskite serve as common indicators of the phase transition to the monoclinic phase that occurs under high pressure application.

The Transformation Mechanism of Graphite to Hexagonal Diamond under Shock Conditions.

The formation of a hexagonal diamond represents one of the most intriguing questions in materials science. Under shock conditions, the graphite basal plane tends to slide and pucker to form diamond. However, how the shock strength determines the phase selectivity remains unclear. In this work, using a DFT-trained carbon global neural network model, we studied the shock-induced graphite transition. The poor sliding caused by scarce sliding time under high-strength shock leads to metastable hexagonal diamond with an orientation relationship of (001)G//(100)HD+[010]G//[010]HD, while under low-strength shock due to long sliding distance cubic diamond forms with the orientation (001)G//(111)CD+[100]G//[110]CD, unveiling the strength-dependent graphite transition mechanism. We for the first time provide computational evidence of the strength-dependent graphite transition from first-principles, clarifying the long-term unresolved shock-induced hexagonal diamond formation mechanism and the structural source of the strength-dependent trend, which facilitates the hexagonal diamond synthesis via controlled experiment.

Insights from the N11 economies on drivers of the clean energy transition

The research literature on the driving mechanisms for the clean energy transition in the Next 11 (N11) economies to accomplish their carbon-free targets is scarce. We address this research gap with an empirical analysis of the effects of renewable fuels, resource allocation, corporate governance, energy trade, economic growth, carbon taxes, and digitalization on the shift to clean energy between 1990 and 2022. Using the method of Moments Quantile Regression, the results show that all regressors enhance the shift to clean energy. Based on the study outcomes, policymakers should intensify their attempts to coordinate policies to support sustainable development goal ambitions.

Onset and propagation of slip at adhesive elastic interfaces.

The transition from static to dynamic friction when an elastic body is slid over another is now known to result from the motion of interface rupture fronts. These fronts may be either cracklike or pulselike, with the latter involving reattachment in the wake of the front. How and why these fronts occur remains a subject of active theoretical and experimental investigation, especially given its wide ranging implications. In this work, we investigate the role of boundary loading in answering this question using an elastic lattice-network model under displacement/velocity controlled loading. Bulk elastic and interface bonds are simulated using a network of springs, with a stretch-based detachment and reattachment rule applied to interface bonds. We find that, contrary to commonly used rigid body models with Coulomb-type friction laws, the type of rupture front observed is very closely linked to the location of the applied boundary displacements. Depending on whether the sliding elastic solid is pulled, pushed or sheared-all equivalent in the rigid case-distinct interface rupture modes can occur. We quantify these rupture modes, evaluate the corresponding interface stresses that lead to their formation, and and study their subsequent propagation dynamics. Our results reveal quantitative analogies between the sliding friction problem and mode II fracture, with attendant wave speeds ranging from slow to Rayleigh. We discuss how these fronts mediate interface motion and implications for the general transition mechanism from static to dynamic friction.

Second-Harmonic-Generation Switching via Pressure-Suppressed Dynamical Disorder.

Second-harmonic-generation (SHG) switching is an emerging phenomenon with potential applications in bistable storage and optical switches while also serving as a sensitive probe for inversion-symmetry. Temperature-induced disorder-order phase transition has been proven to be a rational design strategy for achieving SHG bi-state switching; however, pressure-sensitive SHG switching via a disorder-order structural transition mechanism is rarely reported and lacks sensitivity and cyclicity as practical switching materials. Herein, we demonstrate the pressure-induced "dynamical disorder-order" phase transition as an effective strategy for triggering SHG and SHG switching in NH4Cl. The "dynamical disorder-order" phase transition of NH4Cl occurring at as low as 1 GPa is confirmed by comprehensive in situ high-pressure XRD, molecular vibrational spectra, and Brillouin scattering spectra. The pressure-induced SHG is responsive to a wide excitation wavelength region (800-1500 nm), and the "off-on" switching is reversible for up to 50 cycles, setting a record for pressure-driven switching materials. It is worth noting that when pressure is further increased to 14 GPa, NH4Cl exhibits another SHG "on-off" switching, which makes it the first triplet SHG "off-on-off" switching material. Molecular dynamics simulations reveal the key role of N-H···Cl hydrogen bonding in the pressure-induced "dynamic disorder-order" mechanism. Finally, we verified that chemical pressure and physical pressure can jointly regulate the SHG switching behavior of NH4X (X = Cl, Br). The pressure-driven "dynamic disorder-order" transition mechanism sheds light on the rational design of multistable SHG switching materials for photoswitches and information storage.

Evolutionary distribution and mode transition in medium frequency from 50 kHz to 5 MHz of argon atmospheric pressure dielectric barrier discharge plasma

Dielectric barrier discharges (DBDs) provide a promising technology for generating non-equilibrium cold plasmas at atmospheric pressure. For both application-focused and fundamental research, it is important to explore the discharge mode transition and electron heating mechanism to enable effective independent tuning of key plasma parameters in a DBD system. In this work, we report numerical studies of the effects of single-frequency excitation on atmospheric argon DBDs, which are carried out in the medium driving frequency (MF) range from 50 kHz to 5 MHz by using a one-dimensional hydrodynamics coupling model. The spatio-temporal evolution of particle density associated with the discharge mode transition and electron dynamic behavior has been investigated. By tuning different components of a single frequency, we observe the electron heating behaviors of the individual modes and mode transitions from the Townsend discharge to the glow discharge in the low frequency to the Ω mode and the hybrid mode in the medium frequency to the α-mode and the γ-mode in the radio frequency. The physical analysis is understood based on these fundamental insights into the plasma physics.

Continuous reduction and phase transformation mechanism of pellets in lumpy zone based on dissected hydrogen blast furnace

The continuous phase transition phenomena and mechanism of pellets in the hydrogen blast furnace is achieved by dissecting the 40m3 hydrogen blast furnace. The results of the dissection reveal that the lumpy zone extends to the bosh of the hydrogen blast furnace (HBF), while it ends at about 2/3 of the stack in traditional blast furnace. The iron oxide (FeOx) began to appear in the upper stack, while the iron started to appear in the lower stack. The reduction rate and metallization rate at the bosh are measured at 95.18% and 95.54%. The content of ferrous oxide (FeO) decreases significantly (measured at 1.73% at the bosh), resulting in an increase in the melting point of the primary slag and a deterioration of its fluidity. FeOx formed in the upper stack continuously diffuses and merges into the gangue, which affects the subsequent transformation of FeOx. FeOx shows a preference for interacting with SiO2, CaO, and MgO, directly influencing the formation of slag in the cohesive zone. These findings offer valuable insights for numerical simulation and research on hydrogen-rich operation.

Laser-induced surface reconstruction to enhance interfacial bonding reliability of CFRP/titanium hybrid joints

Adhesive bonding is widely used in aeronautical carbon fiber-reinforced polymer (CFRP)/titanium (Ti) alloy hybrid structures to satisfy the demands of high-strength and lightweight. The physicochemical properties of adherend surfaces significantly impact the bonding performance. In this study, laser-induced surface reconstruction (LISR) was designed for the reliable joining of Ti alloy and CFRP. A three-level-three-factor central composite design (CCD) approach-based response surface methodology (RSM) analysis was applied to statistically specify parameter optimization of the laser energy output. Surface morphology and wettability of CFRP ablated were studied. Chemical compositions were determined by X-ray photoelectron spectroscopy (XPS). Tensile-shear tests were performed, and fractured surfaces were analyzed. The tensile shear strength with LISR process has been improved by 19.1%, in comparison with that of mechanical grinding treatment. The cross-like texture based on designed geometric configuration was fabricated without damaging the underlying fibers, thus increasing the surface roughness and contact area at interface. The wettability transition mechanism was investigated, demonstrating that the hydrophilicity of reconstructed surfaces primarily attributes to the more polar groups (C–O, CO, etc.) on CF surfaces. This study provides a reliable surface treatment method for fabricating high-performance composite structures by adhesive bonding.

Degradation of the mechanical properties of NbMoTaW refractory high-entropy alloy in tension

The mechanical properties of the bcc refractory high-entropy alloy (RHEA) NbMoTaW with columnar and equiaxed microstructures and a nanoscale metal oxide layer on the grain boundaries are investigated at ambient temperatures (RT) to 1200 °C. Under compression, the alloy shows a yield strength, σy, of ⁓1390 ± 20 MPa at RT and retains a high yield strength, σy, of ⁓301.5 MPa at 1200 °C. However, in tension, the fracture strengths, σf, of both columnar and equiaxed microstructures are far lower - below 70 MPa - and the material fails in the elastic regime without showing any measurable ductility at all temperatures. The fracture mechanisms in tension transition from transgranular cleavage at RT to a mixture of transgranular and intergranular fracture at 800 °C to a complete intergranular fracture at 1200 °C due to selective weakening of the metal oxide layer on the grain boundaries driven by a structural change. The transition in the fracture mechanism in the equiaxed microstructure promotes extrinsic toughening at higher temperatures, resulting in a ⁓6.4 times higher fracture toughness (KIc ⁓10.3 MPa√m) at 1200 °C compared to that at RT. NbMoTaW is a well-known RHEA, but the poor tensile strength and fracture toughness measured in this study highlight the critical importance of investigating the mechanical properties of these high-temperature RHEAs in tension.

Stage development characteristics of oxygen-lean combustion of coal in fire zone: Leap-migration mechanism, kinetic transition mechanism, and critical oxygen concentration

Effectively preventing the re-ignition of fire zones and safely unsealing enclosed fire zones are challenging. To address these issues, a thermogravimetric analysis technique was used to explore the leap-migration mechanism of the characteristic parameters (burnout index (H), comprehensive combustion performance parameters (Cb, S, and HF), and maximum combustion mass loss rate (dWmax))/temperatures (maximum pyrolysis mass loss rate point temperature (TVmax), pyrolysis endpoint temperature (Td), thermal polycondensation endpoint temperature (Tp), maximum combustion mass loss rate point temperature (TWmax), burnout temperature (Th), and combustion half-peak width (ΔT1/2)) of low-rank coal oxygen-lean combustion under different time-scale effects (TSEs). The sensitivity of characteristic parameters/temperatures to changes in oxygen concentration under coal rank transition was analyzed. Simultaneously, the kinetic real-time transformation mechanism during the oxygen-lean combustion stage progression was investigated. The results revealed that because of the competition between oxidation and pyrolysis, the leap-migration interval of characteristic parameters/temperatures for oxygen-lean combustion of low-rank coals is in the range of 5 %–3% oxygen concentration. This feature was less affected by the coal rank but is not affected by the TSE. In the low oxygen-lean range (5 %-1%), a change of oxygen concentration was more sensitive to the coal rank, and the high sensitivity of the oxygen concentration change reduced the influence of the coal rank on coal combustion performance. In addition, the apparent activation energy (Eα) curves during the early stage of combustion were relatively concentrated with the change of oxygen concentration, but relatively dispersed during the late stage of combustion. At 3 % oxygen concentration, the Eα values of different coals began to continuously decrease with increasing conversion rate, approaching the spontaneous reaction activation energy value of 40 kJ/mol. At oxygen concentration of 1 % reflected the complete limitation of the oxidation consumption reaction. Therefore, the critical oxygen concentration of typical low-rank coal oxygen-lean combustion was determined below 3 % oxygen concentration. The results of this study can provide scientific guidance for the unsealing of fire zones, and the effective prevention and control of the formation of new fire zone disasters.

Molecular Dynamics Investigation of Metastable Structure and Hybridization Bond Evolution in High-Entropy CoCrFeNi Heterostructured Amorphous Carbon Films.

Heterogeneous element doping in amorphous carbon films can reduce residual stresses and improve plastic deformation. Nevertheless, the effects of dopant content and size on the metastable transition mechanism between sp2-C and sp3-C atoms during the deformation process are unclear and difficult to be in situ observed and researched, experimentally. In this work, the mechanical properties and the structural evolution during the nanoindentation of amorphous CoCrFeNi sphere-doped carbon heterostructured films with different radii were simulated. The results indicate that the hardness H and elastic modulus E of the films decreased with the increase of the dopant addition. H decreases from 50.69 to 28.94 GPa, and E decreases from 664.39 to 448.62 GPa. The decrease in the elastic recovery and the enlargement of the shear transition zones indicate that the presence of the amorphous CoCrFeNi dopant can significantly improve the plastic deformation capacity of the films. During the nanoindentation process, the spherical dopants reduce the stress and shear strain of the regions under the indenter in a-C films. The reduction of compressive and shear stresses in the film can inhibit the C atom metastable transition from sp2-C to sp3-C. This can provide a theoretical basis for the development and design of heavy-load and high-deformation-rate a-C films.