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The influence of defects on the plastic properties of materials always captures much attention for ultrahigh strain-rate loading. By virtue of the planar shock compression in [0001], [ 10 1 ¯ 0 ] , and [ 1 ¯ 2 1 ¯ 0 ] directions, our large-scale molecular dynamics simulations reveal that the prismatic nanopores facilitate the inelastic deformation, such as basal and prismatic glides, reorientation, and amorphization. And that, the nanopores with different center axial directions contribute to activation of various slip systems, such as basal and prismatic dislocation slip. The inelastic deformation induced nanopore collapse is an important mechanism of nanopore collapse at weak shock intensity. Three modes of collapse are obtained: a transverse and a longitudinal collapse from the basal glide, and an inclined collapse from the amorphization at the tip of the prismatic nanopore. The shear stress is highly concentrated at the elastic region about to be plastic deformation, and then attenuates mainly during inelastic deformation and nanopore collapse. The shock energy dissipation is correlated to the conversion between kinetic energy and internal energy, which leads to a higher local temperature around the prismatic nanopore. [ABSTRACT FROM AUTHOR]

W-Ni-Fe tungsten heavy alloys (WHAs) are a kind of ductile phase toughened composites that are becoming increasingly interesting as promising alternatives to monolithic tungsten for fusion reactor plasma-facing materials, because of their outstanding combination of strength, ductility and toughness. Understanding the radiation-induced microstructural features of WHAs associated with their mechanical property changes is therefore a topic of active research. The theoretical study of radiation-induced collision cascades by means of atomistic simulations such as classical molecular dynamics (MD) is highly desirable to provide a detailed analysis for the atom-level primary damage production. Here, we develop a Finnis–Sinclair type interatomic potential for W-Ni-Fe ternary systems based on previously proposed unary W and Fe potentials, and use it to study the point defects and mechanical properties of WHAs. The developed potential yields the bulk and defect properties of pure Ni that are in good agreement with experimental data and density functional theory calculations. In addition, it is also capable of reproducing alloy properties with a satisfactory accuracy, especially regarding the solute migration energies, as well as the ground-state interstitial defect configurations. The constructed potential further shows reasonable transferability to other mechanically relevant properties that are not contained in the fitting database. The present potential here will enable large-scale MD simulations of cascade, deformation and fracture of WHAs. [ABSTRACT FROM AUTHOR]

Tungsten (W)-based high-entropy alloys (HEAs) have shown promising properties as nuclear fusion materials. Characterizing the primary damage is a critical step in describing and revealing the irradiation-induced damage and radiation resistance mechanism. However, there are a limited number of studies on collision cascades and primary radiation damage in W-based HEAs, owing to the large amount of calculations involved and a lack of appropriate interatomic interaction potentials. In this work, we developed a semi-empirical interatomic potential for W–Ta–Cr–V. By using the developed potential, molecular dynamics simulations of collision cascades in W-based HEAs were performed to assess the primary damage due to irradiation. Based on experimental samples, we reported defect production in W 38 Ta 36 Cr 15 V 11 and compared it to pure W for primary knock-on atom with energies ranging from 1 keV to 100 keV. Our findings showed that the number of FPs at the thermal spike and the number of surviving FPs at the end of the cascade in W 38 Ta 36 Cr 15 V 11 are more than those in pure W, mainly due to the lower threshold displacement energy, melting temperature, and formation energy of point defects. Collision cascades in the W 38 Ta 36 Cr 15 V 11 are less likely to result in the formation of dislocation loops compared to pure W. After collision cascade, in W 38 Ta 36 Cr 15 V 11 , the concentrations of Cr and V atoms in defects is significantly higher than their corresponding concentrations in the system, showing an aggregation tendency. The current collision cascade results provide insights into the primary damage of W-based HEA system under irradiation and should provide reliable guidance for describing the primary damage source terms needed in the kinetic models used to simulate radiation-induced microstructural evolution. [ABSTRACT FROM AUTHOR]

Different behaviours of noble gas X (X = He or Ne) atoms in the bulk and on the surface of tungsten (W) have been studied with molecular dynamics simulations to explore the fuzz formation induced by different noble gas bubbles. The formation of X clusters and bubbles in bulk W were simulated at temperatures from 400 to 2000 K. The results showed that higher temperature promotes the nucleation of X bubbles, and the sizes of self-interstitial atoms and X-vacancy clusters of Ne in W were larger than those of He in W at nano-scale, which indicates that Ne atoms can be trapped more easily than He atoms in W. The continuous nucleation processes of He/Ne bubbles near the surface of bulk W were also simulated. When the sizes of the X bubbles were large enough, the behaviour of dislocation loop punching was observed for both He and Ne clusters. From the comparison of the pressure of He/Ne bubble, it is found that the He-bubble can induce the loop-punching with lower critical pressure than the case of Ne-bubble. These results indicate a new understanding of noble gas effects in W in fusion reactors. [ABSTRACT FROM AUTHOR]

High-energy collision cascades with an energy of up to 300 keV for the primary knock-on atom (PKA) have been initially simulated in W and W–Re alloys containing 5 or 10 at.% Re atoms using the molecular dynamics method with recently fitted W–Re interatomic potentials. The effects of PKA energy and Re concentration on defect production, defect clustering and states of dislocation loops have been quantitatively analysed. The results show that the presence of Re atoms does not significantly affect either the number of surviving defects or their clustered fractions. In addition, the interstitial dislocation loops are dominated by the 1/2<111 > loops. Mixed interstitial loops with 1/2<111> and <100> Burgers vectors and interstitial loops that have the same Burgers vectors but are located on different habit planes have also been observed. Further analysis indicates that the pinning effect induced by the Re atom segregation leads to the lower mobility of the interstitial clusters and interstitial 1/2<111> loops in W–Re alloys than in pure W, which is expected to influence the subsequent evolution of radiation-induced defects in W–Re alloy. • Formation of completed 1/2<111> and mixed 1/2<111>−<100> interstitial loops during high-energy neutron cascades in W and W–Re alloys. • High-energy cascade induces a unique loop configuration taking the same Burgers vector but locating on different habit planes. • Re does not significantly affect the number of surviving defects. • Re reduces the mobility of the interstitial clusters and loops. [ABSTRACT FROM AUTHOR]

Tungsten (W) and W-based alloys are the leading candidates for plasma-facing materials (PFMs) in future fusion reactors. However, the high energy neutrons generated in fusion reactions not only result in cascade damages but also cause W transmutation. Both the irradiation defects and transmutation products, mainly rhenium (Re), have serious effects on the service behaviors of W PFMs. In this work, we have systematically investigated the interaction between Re and the self-interstitial atoms, self-interstitial clusters and 1/2<111> interstitial dislocation loops in bulk W using molecular dynamics and statics simulations. It is found that there is a strong attractive interaction between an interstitial W atom and a substitutional Re atom, forming a Re–W dumbbell that migrates 3-dimentionally due to the low migration and rotation energies. The small SIA clusters strongly bind with both the substitutional Re atoms and an interstitial Re atom (Re–W mixed dumbbell), thus decreasing the mobility of these clusters. The strong attractive interaction between a Re atom and a 1/2<111> interstitial dislocation loop occurs when the Re atom is located at the core of the loop, and also, their interaction distance along <111> direction is large. The mobility of the 1/2<111> interstitial dislocation loop decreases progressively with increasing Re concentration. • An optimized W–Re empirical potential has been developed. • The interactions between Re and interstitial defects and dislocation loops in W have been systematically investigated. • There is a strong attractive interaction between Re atoms and interstitial-type defects. • The presence of Re atoms reduces the mobility of the self-interstitial clusters and 1/2<111> interstitial dislocation loops. [ABSTRACT FROM AUTHOR]

• New interatomic potentials of Ta-Ta and W-Ta based on F-S formalism have been developed. • The formation energies of point defects and the non-degenerate core structure of a 1/2 〈1 1 1〉 screw dislocation in Ta bulk are well reproduced. • The developed potentials have high accuracy and good transferbility. • These potentials are applicable for describing the evolution of point defects in Ta and W-Ta alloys. Tungsten (W) and W-based alloys are regarded as the most promising candidates for plasma facing materials (PFMs) in future fusion reactors. In this work, new interatomic potentials for Ta element and W-Ta alloy have been developed based on the Finnis-Sinclair formalism, in combination with our previously developed potential for W. The potential parameters for Ta were determined by fitting to a set of experimental and first-principles data, including lattice constant, cohesive energy, elastic constants, point defects formation energies and Rose's equation of state for the bcc lattice. The W-Ta cross parameters were fitted to the first-principles data of the formation energies and binding energies of Ta atom with different point defects in bulk W. The present potentials not only reproduce some important physical properties of various point defects, but also predict the non-degenerate/compact core structure of the 1/2 〈1 1 1〉 screw dislocation in bulk Ta, which is the same as DFT calculations. The developed potentials were expected to be suitable for atomistic simulations of point defects evolution in Ta and W-Ta binary alloys. [ABSTRACT FROM AUTHOR]

An important goal of systems medicine is to study disease in the context of genetic and environmental perturbations to the human interactome network. For diseases with both genetic and infectious contributors, a key postulate is that similar perturbations of the human interactome by either disease mutations or pathogens can have similar disease consequences. This postulate has so far only been tested for a few viral species at the level of whole proteins. Here, we expand the scope of viral species examined, and test this postulate more rigorously at the higher resolution of protein domains. Focusing on diseases with both genetic and viral contributors, we found significant convergent perturbation of the human domain-resolved interactome by endogenous genetic mutations and exogenous viral proteins inducing similar disease phenotypes. Pan-cancer, pan-oncovirus analysis further revealed that domains of human oncoproteins either physically targeted or structurally mimicked by oncoviruses are enriched for cancer driver rather than passenger mutations, suggesting convergent targeting of cancer driver pathways by diverse oncoviruses. Our study provides a framework for high-resolution, network-based comparison of various disease factors, both genetic and environmental, in terms of their impacts on the human interactome. [ABSTRACT FROM AUTHOR]

• A new reliable F-S potential of Y is developed and further validated under static and dynamic conditions. • The atomistic mechanism of HCP → Sm-type → DHCP → FCC phase transition is characterized by the minimum energy path for shock along the [10−10] direction. • Amorphization mediates the phase transition process for the [0001] and [−12−10] shock directions, and then rapidly annihilates and recrystallizes to FCC lattices. • The uniaxial compression strains in the [0001] and [−12−10] shock directions inhibit the formation of Sm-type and DHCP phases. The insightful understanding of phase transition in rare earth elements under shock compression is significant to the future development of materials science. In this work, a new reliable Finnis-Sinclair interatomic potential for hexagonal close-packed (HCP) single crystal yttrium (Y) is developed and validated. The potential reproduces the phase transition sequence of HCP → Sm-type (samarium-type) → DHCP (double hexagonal-close-packed) → FCC (face-centered-cubic) of Y observed in high-pressure experiments. Further, large-scale NEMD simulations are conducted to study shock compression behaviors of Y. For the [10−10] HCP shock direction, the HCP → Sm-type phase transition occurs via an intermediate metastable BCC structure, which is accomplished by atomic shuffles and shear. Then, a pure-shear along the [10−10] Sm-type direction transforms the Sm-type to DHCP structure. Besides, we find FCC phase can be generated by shifting the atoms at two layers in opposite <10−10> directions on {0001} planes in the DHCP lattice. Combined with the transition state theory, we confirm these transition pathways follow the minimum energy path. For shock along the [0001] HCP and [−12−10] HCP directions, the HCP → FCC phase transition is mediated by the amorphization which subsequently annihilates and turns to recrystallize to be FCC lattice. The results suggest that the uniaxial compression strain along the [0001] HCP and [−12−10] HCP directions hinders the formation of Sm-type and DHCP phases. Our findings provide essential insights into the phase transition behavior of Y under shock loading. [Display omitted] [ABSTRACT FROM AUTHOR]

Tungsten (W) and W-based alloys have been considered as promising candidates for plasma-facing materials (PFMs) in future fusion reactors. The formation of rhenium (Re)-rich clusters and intermetallic phases due to high energy neutron irradiation and transmutations significantly induces the hardening and embrittlement of W. In order to better understand these phenomena, in the present work, new interatomic potentials of W-W, Re-Re and W-Re, suitable for description of radiation defects in such alloys, have been developed. The fitted potentials not only reproduce the results of the formation energy, binding energy and migration energy of various radiation defects and the physical properties from the extended database obtained from DFT calculations, but also predict well the relative stability of different interstitial dislocation loops in W, as reported in experiments. These potentials are applicable for describing the evolution of defects in W and W-Re alloys, thus providing a possibility for the detailed understanding of the precipitation mechanism of Re in W under irradiation. [ABSTRACT FROM AUTHOR]

• The interaction of cascade with a pre-existing Cr-rich precipitate slightly increased the number of surviving Frenkel pairs. • A 2 nm pre-existing precipitate could be completely dissolved by intermediate-high energy cascades. However, the 3 and 5 nm precipitates exhibit slight modifications. • The cascade significantly decreased the average Cr content in the precipitate to ∼45% with concomitant increases in the Fe and Al contents from the high energy cascade. • An amorphous transformation of the 2-nm precipitate occurred in the displacement damage. The formation of Cr-rich α ' precipitates in irradiated Fe-Cr-Al alloys has been recognized as a leading microstructural feature causing significant radiation-induced hardening and embrittlement. In this work, the stability of a pre-existing α ' precipitate under cascade damage and its effect on cascaded-induced defects in an Fe-15Cr-8Al ternary alloy were investigated through molecular dynamics simulations. We mainly focused on the behavior of Cr-rich precipitates under the different cascade conditions. This atomic-scale study of cascades, with and without a Cr-rich precipitate, showed that the interaction of cascade with the pre-existing precipitate slightly increased the number of surviving Frenkel pairs and enriched the level of Cr atoms as interstitials. In addition, the presence of the Cr-rich precipitate did not considerably affect the fraction of defects in clusters and cluster size. In turn, the 2-nm precipitate could be completely dissolved under intermediate-high energy cascades (30 and 50 keV), but large precipitates (with the diameters of 3 and 5 nm) exhibited only slight modifications. Moreover, the changes in the chemical composition and microstructure of the precipitate were discussed. The cascade significantly decreased the average Cr content in the precipitate (up to ∼45%) with concomitant increases in the Fe and Al contents from the high-energy cascades. Also, it was of interest to note the amorphous transformation of a 2 nm Cr-rich precipitate occurred in the displacement damage. [Display omitted] [ABSTRACT FROM AUTHOR]

• The displacement cascade simulations in pure W and W-Re alloy containing GB and/or σ-phase have been systematically investigated. • Interstitials in W-Re alloy are preferentially absorbed by GB region. • Interstitials are preferentially absorbed by σ-phase, and Re atoms tend to aggregate near the σ-phase region. • The absorption of σ phases and the GB region leads to an increase in the aggregation of interstitials near the σ phase/GB region and a reduction of vacancies in the bulk region Transmutation rhenium (Re) produced in tungsten (W) neutron irradiation not only segregates and precipitates at grain boundaries (GBs) but also forms the σ-phase (WRe) in the bulk. In this study, using a molecular dynamics (MD) method, we conducted collision cascade simulations in W and W–Re alloys with 5 or 10 at% Re atoms containing a GB/σ-phase and systematically examined the effect of GB and the evolution of σ-phase. We find the interstitials in W-Re alloy are preferentially absorbed by the GB region such that the number of vacancies in the bulk region is higher in W–Re alloys than in W; the defect distribution is sensitive to the distance of primary knock-on atoms from the GB plane. Furthermore, similar to the tendency in the GB region, interstitials are preferentially absorbed by the σ-phase, and Re atoms tend to aggregate near the σ-phase region. The absorption of σ-phases and the GB region leads to a considerable defect aggregation, which provides suitable conditions for the regrowth of σ-phase structure during long-term evolution. The results provide a reference for understanding the GB structure and precipitations in the displacement cascades of W and W-based alloy materials. [ABSTRACT FROM AUTHOR]

• Interatomic potential for V-Ti-Ta ternary system based on F-S formalism has been developed. • The Ti potential well reproduce the point-defect properties of vacancy and self-interstitial atoms and the pressure-volume relation. • The typical defect energies of solute atoms Ti and Ta in the V matrix and Ti and V in the Ta matrix predicted by the present potential were in good agreement with DFT results. Vanadium (V)-based alloys are potential candidates for structural materials of fusion reactors because of their excellent properties; recently, the V–Ti–Ta alloy has received considerable attention. The irradiation-resistant performance is significant for the development and application of fusion reactor materials. In this study, combining with our previously developed potentials of V and Ta, we developed the V-Ti-Ta interatomic potential based on the Finnis–Sinclair (FS) formalism, which is an important step towards an atomic-scale investigation of V-based alloys. The potential parameters were determined by fitting to a large database of experimental data and density functional theory (DFT) calculations. The formation energies of vacancy and self-interstitial atoms, as well as the pressure-volume relation obtained from the present Ti potential, were well reproduced. The typical defect energies of solute atoms Ti and Ta in the V matrix and Ti and V in the Ta matrix, such as the formation energies of substitutional solute atoms, binding energies between solute atoms and point defects, agree well with DFT results. Thus, the developed potentials are expected to be suitable for atomistic simulations of point defects evolution in the V-Ti-Ta ternary system. [ABSTRACT FROM AUTHOR]

l Ta does not significantly influence the primary damage state, in terms of number of surviving defects or clustered fraction. l Ta reduces the mobility of the interstitial clusters and 1/2<111> interstitial loops. l The presence of Ta has a stabilizing effect on the 〈100〉 loops at high-temperature. Tungsten (W) and W-based alloys are competitive candidates for plasma-facing materials in future fusion reactors. W-tantalum (Ta) alloys get the most attention amongst these materials. The present study uses molecular dynamics simulations to study the displacement cascades of pure W and W-Ta alloy systems with recoil energy up to 100 keV at 300 K and the further evolution of cascade defects at 1,000 K. The effects of Ta concentration on the generation and evolution of the defects, produced with primary knock-on atom energies, are quantitatively analysed. This study's results show that the presence of randomly distributed Ta atoms does not significantly affect the average number of surviving Frenkel pairs or the fractions of clustered vacancies and interstitials. In addition, there is no completed vacancy dislocation loop in all systems after cascading. The produced dislocation loops are mainly 1/2 〈111〉 loops companied with a small amount of 〈100〉 loops and mixed loops. However, the existence of Ta atoms slows down the motion of defects and defect mobility decreases as the Ta concentration increases in bulk W. This will affect the size and density of defects. In addition, the presence of Ta also inhibits the transition of the 〈100〉 dislocation loops to 1/2 〈111〉 dislocation loops under the high-temperature condition. This will affect the types of dislocation loops and the material performance. [ABSTRACT FROM AUTHOR]

In this paper, we present an interatomic potential for the ternary W–Ta–He system, which is an extension of our previous W–Ta potential. The new potential parameters for the W–He and Ta–He interactions are determined by fitting the results obtained from first-principles calculations. The formation energies of a single He atom at different sites, the binding energies of He–He and He–Vac (Vac = vacancy) in W/Ta, and the binding energies of a single He atom with a solute Ta atom in W are used as the fitting targets. Then, the binding energies of an additional interstitial He atom to existing He n Vac m clusters in W/Ta are calculated, and the results reported correspond with the results from the first-principles. Furthermore, the effects of solute Ta on the diffusion and aggregation of He in bulk W are studied. We observed that small interstitial He atom clusters (N He ≤ 4) were easy to diffuse in pure W, and their diffusion activation energies were less than 0.3 eV. However, the binding energies between Ta and these clusters were between 0.5 and 0.9 eV, which has a pinning effect on the He cluster diffusion. At high temperature, the solute Ta cannot qualitatively hinder the agglomeration of He atoms, however, due to the pinning effect compared with pure W, solute Ta in W has a certain delay effect on the agglomeration of He atoms in time. [ABSTRACT FROM AUTHOR]

The microscopic mechanism of the effect of alloying element on the shock behavior for alloy materials is still limited. In this work, based on our developed Finnis–Sinclair (F–S) interatomic potential of Mg-Y alloy, using nonequilibrium molecular dynamics (NEMD) simulations, we gave new insights into the role of alloying element Y in dynamic deformation of Mg-xat.%Y (x = 1, 3, 6, 8 and 10) alloys, and further revealed the deformation mechanisms of these solid solution alloys, which is dependent on the compositions of Y and the crystallographic orientations. The results confirm that the lattice instability caused by Y atoms results in the reduced yield stress. Under shock along the [0001] direction, the improved plasticity is mainly attributed to the increasing amorphous activity and decreasing amorphous annihilation rate with Y additions, but the other mechanisms, e.g., the dislocation nucleation and phase transition, are suppressed. Furthermore, for the [10 1 ¯ 0] direction, the energy barriers of stacking faults and disordering can be overcome at high Y content, so these two deformation modes are activated accompanying with the lattice reorientation to release the large internal stress, and the enhanced plastic activity is mainly related to the inhibited phase transition. This work can broaden the knowledge of the dynamic response of Mg-Y alloys at atomic-scale, which is significant for the shock experiments and material design. [Display omitted] • Lattice instability around Y atoms results in the reduced yield stress. • Increasing amorphous activity with Y additions improves plasticity in Mg-Y alloys. • Energy barriers of diverse deformation modes can be overcome at high Y content. • Inhabited phase transition enhances the plastic activities of Mg-Y alloys. [ABSTRACT FROM AUTHOR]

Interatomic potentials for tungsten–vanadium (W–V) and tungsten–molybdenum (W–Mo) binary systems have been developed based on Finnis–Sinclair formalism. The potentials are based on an accurate previously developed potential of pure W. Potential parameters of V–V, Mo–Mo, W–V and W–Mo were determined by fitting to a large database of experimental data as well as first principle calculations. These potentials were able to describe various fundamental physical properties of pure V and Mo, such as a lattice constant, cohesive energy, elastic constants, bulk modulus, vacancy and self-interstitial atom formation energies, stacking fault energies and a relative stability of <100> and ½<111> interstitial dislocation loops. Other fundamental properties of the potentials described included alloy behaviours, such as the formation energies of substitutional solute atoms, binding energies between solute atoms and point defects, formation energies and lattice constants of artificial ordered alloys. These results are in reasonable agreement with experimental or first principle results. Based on these results, the developed potentials are suitable for studying point defect properties and can be further used to explore displacement cascade simulations. • Interatomic potentials for W–V and W–Mo binary systems based on F–S formalism have been developed. • The developed potentials are applicable for studying the point defect properties and displacement cascade simulations. • These potentials also provide a basis for fitting the interatomic potentials of tungsten-based multi-element alloys. [ABSTRACT FROM AUTHOR]

• The interactions between Re and Σ5(130) grain boundary in W have been systematically investigated. • GBs are sinks for Re atoms through interstitial or vacancy assisted mechanisms. • Re atoms are more likely to locate at substitutional sites nearby the GB in kinetic segregation process. • Re clusters have strong effect on impeding the plastic deformation of the GBs, and may cause the embrittlement of materials. High energy neutron irradiation not only causes the transmutation of tungsten (W), but also induces transmutation elements to segregate and precipitate at grain boundaries. In this work, the segregation of transmutation-produced rhenium (Re) and their clusters at a Σ5(130) grain boundary (GB) in bulk W has been investigated by using both molecular dynamics and molecular statics methods. It is found that, for single interstitial, Re atom diffuses from the bulk to the GB region via a three-dimensional rotation and migration in the form of an interstitial 〈1 1 1〉 Re-W mixed dumbbell, because the rotation and migration barriers of a Re-W dumbbell are both small. When Re atoms are absorbed by the GB, it is noteworthy that Re atoms tend to occupy the substitutional sites near the GB. The segregation energy of interstitial Re is ranged from −7.67 to −6.12 eV, and the effective interaction distance between the GB and Re interstitials is about 7 Å, which increases with increasing the cluster size. By modeling the uniaxial tensile test of W-GB structure containing Re substitution clusters, the fracture strength and elongation of the GB are significantly reduced. The present results provide important insights into the detailed mechanisms of Re segregation at GBs and its possible effects on the mechanical properties of W-based materials. [ABSTRACT FROM AUTHOR]

Purpose: No consensus on a grading system for invasive lung adenocarcinoma had been built over a long period of time. Until October 2020, a novel grading system was proposed to quantify the whole landscape of histologic subtypes and proportions of pulmonary adenocarcinomas. This study aims to develop a deep learning grading signature (DLGS) based on positron emission tomography/computed tomography (PET/CT) to personalize surgical treatments for clinical stage I invasive lung adenocarcinoma and explore the biologic basis under its prediction. Methods: A total of 2638 patients with clinical stage I invasive lung adenocarcinoma from 4 medical centers were retrospectively included to construct and validate the DLGS. The predictive performance of the DLGS was evaluated by the area under the receiver operating characteristic curve (AUC), its potential to optimize surgical treatments was investigated via survival analyses in risk groups defined by the DLGS, and its biological basis was explored by comparing histologic patterns, genotypic alternations, genetic pathways, and infiltration of immune cells in microenvironments between risk groups. Results: The DLGS to predict grade 3 achieved AUCs of 0.862, 0.844, and 0.851 in the validation set (n = 497), external cohort (n = 382), and prospective cohort (n = 600), respectively, which were significantly better than 0.814, 0.810, and 0.806 of the PET model, 0.813, 0.795, and 0.824 of the CT model, and 0.762, 0.734, and 0.751 of the clinical model. Additionally, for DLGS-defined high-risk population, lobectomy yielded an improved prognosis compared to sublobectomy p = 0.085 for overall survival [OS] and p = 0.038 for recurrence-free survival [RFS]) and systematic nodal dissection conferred a superior prognosis to limited nodal dissection (p = 0.001 for OS and p = 0.041 for RFS). Conclusion: The DLGS harbors the potential to predict the histologic grade and personalize the surgical treatments for clinical stage I invasive lung adenocarcinoma. Its applicability to other territories should be further validated by a larger international study. [ABSTRACT FROM AUTHOR]

Radiation-induced defects are the significant cause of radiation damage in austenitic stainless steels. In this work, the interactions between a screw dislocation and stacking fault tetrahedrons (SFTs) are studied in Fe–10Ni–20Cr (a model alloy of austenitic stainless steel) and Ni, using molecular dynamics simulations. Four interaction processes were primarily found, including (1) partial absorption, (2) sheared, (3) bypassing, and (4) restored through double cross-slip. In Fe–10Ni–20Cr alloys, there is almost no correlation between the critical resolved shear stress (CRSS) value and SFT size, but the intersection position largely impacts the results. And the CRSS value decreases with temperature increasing in Fe–10Ni–20Cr. The occurrence of cross-slip has a significant effect on the interactions, and there exist greater CRSS value in the interactions of cross-slipping. Besides, the occurrence of the cross-slip is linked to the stacking fault energy and the distribution of solute atoms of the alloys. [ABSTRACT FROM AUTHOR]

In this work, we have carried out a series of displacement cascade simulations in tungsten (W), including seven different primary-knock-on atom (PKA) directions, and PKA energy covers 1 to 300 keV at 363 K; 10, 50, 100, and 200 keV cascades are considered at 600 K, and 10 and 50 keV cascades are simulated at 300 K. Then, a systematic database of W cascade simulations has been established, containing more than 2000 cascades. The number of Frenkel pairs, the type of defect, and its spatial distribution were all determined. The effects of PKA direction, PKA energy and temperature have been discussed in terms of defect generation, defect clustering, and dislocation loops. It is found that, the PKA direction may have an effect on the configuration of defects, such as the formation probability of 〈100〉 interstitial loops, C15 clusters and the sub-cascades, and also has an effect on the number of Frankel pairs when PKA energy larger than 50 keV. Furthermore, from 363 K to 600 K, the number of Frankel pairs is reduced by ∼10%, and high temperature can promote the clustering of interstitial. We further found that temperature may affect the distribution of dislocation loops, and the number of 〈100〉 interstitial dislocation loops is more at 363 K than at 600 K. These results can provide a database of key input parameters for the subsequent larger-scale simulations, and give an important reference for the prediction of defect behaviour, mechanical and thermal properties of W-based materials under fusion neutron irradiation. [ABSTRACT FROM AUTHOR]

U-10Zr metallic fuel (alloys of U with 10 wt% Zr) is considered as a potential candidate for fast reactors due to its excellent performance. However, the fission gas swelling has a significant impact on its properties and prevents it from reaching higher burnup. To gain a deeper understanding of the fission gas swelling mechanism, molecular dynamics simulations based on interatomic potentials are underway to fill the key knowledge gaps. In this work, two modified embedded-atom method (MEAM) potentials are developed for the U-Zr system with Xe, one for α-U-Zr and δ-UZr 2 , and the other for γ-U-Zr. The parameters of the potentials are determined by fitting the material properties from experiments or density functional theory (DFT) calculations. It is verified that the potentials can reproduce well the lattice constants, elastic constants, point defects, surface energy, and the melting point of U. In addition, the lattice constants, elastic constants, cohesive energy, and point defect formation energy of Zr are in good agreement with the experimental and DFT results. For the alloy system, the typical defect properties of Zr and Xe in U, as well as the formation energy and elastic constant of δ-UZr 2 are close to the DFT. The lattice constant, linear thermal expansion, and mixing enthalpy of γ-U-Zr alloy are following the experimental values. The results show that the obtained potentials are suitable for simulating the defect evolution and Xe behaviors in the U-Zr system. [ABSTRACT FROM AUTHOR]

Fe–Cr–Al alloys have the potential to form a crucial class of enhanced accident tolerant fuel cladding materials in light water reactor due to their excellent oxidation resistance in high temperature steam environments. The irradiation resistant performance is also significant for the development and application of fission and fusion reactor materials. In this work, we developed a Fe–Cr–Al interatomic potential based on the Finnis–Sinclair (F–S) formulism, which can be used to describe the defect properties in Fe–Cr–Al alloys. The potential parameters for Fe–Cr–Al alloys were determined by fitting to a set of experimental results and density functional theory (DFT) calculations. Specifically, the formation energies of self–interstitial atoms and the stacking fault energy obtained from the present Al potential are consistent with the DFT results. The point–defect properties of Fe–Cr and Fe–Al alloys determined with the DFT calculations, such as the mixed (both Fe–Cr and Fe–Al) or pure (both Cr–Cr and Al–Al) dumbbells and the substitutions (both Cr and Al atoms) in the body–centered cubic (bcc) Fe matrix, are well reproduced by our atomistic simulations. Consequently, this parameterized potential is expected to be capable for atomistic simulations of irradiation defects and defect evolution in Fe–Cr–Al ternary systems. [ABSTRACT FROM AUTHOR]

It has long been recognized that grain boundary (GB) is an effective sink to trap irradiation-induced defects. Introducing large densities of GBs becomes an effective strategy to enhance irradiation resistance. However, the nano-grained materials have poor stability under the extreme irradiation, and the effect of nano-GB characters on the irradiation sink strength is largely unknown. Here, the sink strength of nano-GB is quantitatively investigated in the nano-grained Cu and dilute Cu–W alloys with the average grain size ranging from ∼20 to ∼50 nm by ∼300 keV He ions irradiation at room temperature and 673 K. The irradiation induced void volume ratio, size and distribution are confirmed to strongly depend on the grain size and irradiation temperature. The nano-GBs with different characters, such as the misorientation and GB plane, have similar relative energy. The nano-GB sink strength is independent on the GB characters, deriving from the highly curved nano-GB plane having excess volume and energy. Combining with molecular dynamics simulations, we can conclude that nano-grain size is the most vital factor for the sink strength with respect to the GB characters. With the increase of temperature and the decrease of grain size, the stable nano-GBs exhibit a behavior of "ideal" defects sink due to their high volume ratio and the increased point defect recombination probability. Our work provides a fundamental understanding of the nano-GB sink efficiency and offer a guidance for designing nano-grained structural materials with optimum anti-irradiation performance for future fusion reactors. Image 1 • Dilute Cu–W alloys exhibit significantly enhanced thermal stability. • Irradiation-induced voids highly depend on grain size and irradiation temperature. • A critical nano-grain size exists for excellent irradiation tolerance. • The nano-GB energy is almost comparable in GBs with different characters. • Nano-GB characters have limited influence on the nano-GB sink strength. [ABSTRACT FROM AUTHOR]

• Interaction between shock waves and 1/2<111> prismatic dislocation loop. • New mechanisms for change of habit plane for 1/2<111> loop under shock loading. • The driving force for changing the loop's habit plane is the resolved shear stress. • Shock-induced plasticity locally at a 1/2<111> dislocation loop in BCC tungsten. • The formation of twins and dislocation network depend on orientation effect. Tungsten (W) is a promising candidate material for future fusion reactors. The shock waves generated under high-energy neutron radiation can lead to the formation of prismatic interstitial dislocation loops (PIDLs). To understand the details of the mechanisms, the interaction between the shock waves and PIDL with Burgers vector of 1/2<111> was studied by using nonequilibrium molecular dynamics (NEMD) simulation. The shock-induced change of habit plane for the 1/2<111> PIDL and plasticity in W depend strongly on the crystallographic orientations. The driving force for changing the loop's habit plane is derived from the resolved shear stress (RSS). A new rotation mechanism is proposed, which can be used to predict the changing trend of PIDL's habit plane. The rotation angle of the habit plane for the 1/2<111> dislocation loop is proportional to the RSS of the activated slip system. In this work, we also predict a source to induce the plasticity (e.g., deformation twin and dislocation network) observed in the experiment and discuss the nucleation, propagation and interaction of these deformations with different crystallographic orientation. The current results provide significant insights into the evolution of 1/2<111> PIDL depending on the crystallographic orientation under shock loading. [ABSTRACT FROM AUTHOR]