Objective: To explore the visual fixation patterns during facial emotion recognition and the association between fixation duration percentage (FDP) of eye region with social impairment among high-functioning autism spectrum disorders (HFASD). Methods: Children were recruited from the Child and Adolescent Behavior Research Center of Sun Yat-sen University, Guangzhou, between July and December 2019 for case control study. A total of 42 children with HFASD and 23 age-and gender-matched typical development (TD) children were enrolled. Based on their performance during the facial emotion recognition task, HFASD children were further divided into ASD-1 group (correctly recognized both happy and fear emotions) and ASD-2 group (recognized happy emotions only). During the free viewing task, an infrared eye tracker was used to record the gazing data of children in the three groups. The social responsiveness scales (SRS) was utilized to evaluate HFASD children's social impairment, with the cutoff score of 75 to differentiate those from mild and severe social impairment. The differences of FDP among the three groups were analyzed by the Analysis of Variance (ANOVA) model. Mixed linear regression model was conducted to evaluate the associations between social impairment and FDP of eye region among HFASD children. Results: The final sample consists of 25 ASD-1 (20 males, aged (7.9±1.0) years), 17 ASD-2(14 males, aged (7.2±1.2) years), and 23 TD (12 males, aged (7.7±1.3) years) children. There were no significant differences in age and gender among three groups (F=2.05, χ²=10.08, P=0.14 and 0.07, respectively). For the happy emotion, there are significant differences in eye FDP among the three groups (TD: 0.37±0.20, ASD-1: 0.35±0.20, ASD-2: 0.47±0.24, F=3.97, P=0.02). Mixed linear regression model revealed that, adjusting for emotion, gender, age and intelligence quotient, ASD children's eye FDP negatively associates with social impairment (OR=0.15, 95%CI: 0.06-0.35, P<0.01). Conclusions: Longer FDP is associated with milder social impairment among HFASD children. HFASD children with facial emotion recognition difficulties require longer fixation to recognize happy emotions.

Improving the thermostability and mechanical properties of metastable amorphous materials are critical for their potential applications. Here we report the achievement of a wide variety of nanostructures and properties in Ni-Nb metallic glass thin films (MGTFs) by tuning the substrate temperature (Tsub) during magnetron sputtering. By gradually increasing Tsub close to glass transition temperature (Tg) from room temperature, we evidence the transition from the hierarchical nanostructure with microcracks to the denser nanostructure with a smoother surface and smaller column/particle size. This transition contributes to the enhanced plastic deformation stability and nanomechanical properties, thermal stability, and optical reflectivity in the visible light wavelength. We explain the nanostructure evolution with Tsub based on the competition between the shadowing effect and surface diffusion. The shadowing effect is dominant in low-Tsub films and promotes the voided boundaries, while surface diffusion is remarkably enhanced at high Tsub (0.76–0.87 Tg) to form dense intergrain boundaries. This finding provides a promising avenue towards producing novel functional MGTFs with controllable nanostructures and properties without any post-treatment.

Crystallization of metallic glasses (MGs) is a complex dynamic process, driven by thermodynamics and limited by kinetics, which often involves phase transformation from the metastable amorphous state, via intermediates, to the final stable crystalline states. The intermediate structural state remains mysterious at present but crucial for a deeper understanding of the physics and mechanisms of the crystallization process. Detailed structural characterization of the complex intermediate crystalline phases using transmission electron microscopy (TEM) provides a unique platform to study such issues. Here, we monitor the evolution of the crystallization process for Ni65Zr35 (at%) MG ribbon with structural heterogeneities. Direct visualization combined with compositional analysis reveal that the intermediate phase with Zr concentration higher than that of the MG consists of stacked nanometer-sized layers of Ni-rich units (Ni at% > 67%) and Ni10Zr7-like units, where the thin Ni-rich single layer gradually disappears with increasing annealing temperature. Our findings provide insight into the key role of Ni in the structural transition process, improving the understanding of the atomic diffusion-dominated crystallization in MGs.

The effects of loading rate on creep behavior and shear transformation zone (STZ) in magnetron sputtered La-Co-Al and Zr-Cu-Ni-Al amorphous alloy thin films were characterized through instrumented nanoindentation with a spherical indenter. It was revealed that with an increase in loading rate, both thin films became harder with a narrower distribution of mechanical response, and exhibited more pronounced creep displacement with higher creep strain rate. Based on cooperative shear model, both STZ volume and activation energy were calculated by measuring the strain rate sensitivity during creep, showing an increasing tendency with loading rate. However, the strain rate sensitivity was found to decrease with loading rate. Furthermore, structural heterogeneity density, estimated by analyzing the stressed volume at yielding, decreased with loading rate. Therefore, with increasing loading rate, the STZ event can only be activated at detectable structural heterogeneities with relatively larger volume, and the number of available fertile sites was decreased, resulting in postponed shear band formation and suppressed deformation mode transition.

The effect of substrate temperature on growth behavior and microstructure-properties correlation of magnetron sputtered Ni60Nb40 films were systematically investigated. With substrate temperature increasing from 293 K to 493 K, and thickness changing from 50 nm to 1 mu m, all films kept in amorphous state. The characteristic of columnar growth was clearly seen, with reduced interfacial fraction between adjacent columns and increased granule size at high substrate temperature. Through scaling analysis, films deposited at all temperatures grow in an anomalous roughening mode, and at 293 K for films thicker than 200 run, a difficult roughening phenomenon was revealed. High substrate temperature can facilitate the surface kinetic roughening. Both decreased interface fraction-to-volume ratio by particle coarsening and reduced free volume by structure relaxation caused the dense atomic atomic packing and increased density, which may be the crucial reason for enhanced mechanical properties and thermal stability against crystallization.

Nanometer-scale phase separation has been explored in an Al60Ge30Mn10 amorphous alloy, where all atomic pairs have negative heats of mixing. Here we use a combination of experimental (X-ray diffraction, X-ray absorption fine structure, small angle X-ray scattering and transmission electron microscopy) and simulation (Ab initio molecular dynamics and reverse Monte Carlo) techniques to resolve the atomic- and micrometer-level structures in the phase-separated Al60Ge30Mn10 amorphous alloy. Three characteristic peaks appear in the structure factor, linking with three kinds of composition fluctuation regions with different heterogeneous structures. The origin of three characteristic peaks is investigated in details and attributed to different atomic pairs. By analyzing the local chemical ordering between main polyhedra, we find that various phases exhibit differences in atomic structure, composition and bond-orientational order. The results obtained here provide atomic-scale understanding of the nanometer-scale phase separation phenomenon in Al60Ge30Mn10 amorphous alloy.

Clarifying the crystallization path, from the thermodynamic point of view, is of importance for the structure and properties of metallic glasses (MGs). The influence of oxygen on the crystallization pathway of Ni65Zr35 MG was investigated by in-situ heating transmission electron microscopy (TEM). As temperature increases, crystalline Ni7Zr2 and t-ZrO2 phases are formed first rather than the Ni10Zr7 and Ni21Zr8 phases, which are the main crystallization products following the phase diagram. Oxygen changes the crystallization pathway by varying the Ni/Zr ratio, indicating that the effects of oxygen on the crystallization in nanometer-sized MG cannot be neglected even in high vacuum TEMs.

Magnetron sputtered thin film metallic glasses (TFMGs) with nanoscale heterogeneities have attracted much interest since they are amorphous materials, whose properties can be tailored. In this work, we investigated the different growth modes observed in magnetron sputtered TFMGs. We sputtered Au-based TFMGs under different working pressures of Ar, ranging from 0.4 to 10 Pa. In addition, the influence of the substrate roughness on the thin film microstructure was studied. Our results show two distinct thin film growth modes: homogeneous at low working pressures and nanostructured with mesoscopic hills and nanocolumns at higher working pressures. We also demonstrate that an increase in substrate roughness promotes the formation of nanostructures such as nanocolumns, even at relatively low working pressures. Our finding shows that the final microstructure of the film originates from a competition of surface diffusivity and shadowing effect.

To develop an excellent low-dimensional magnetic material, the evolution of microstructure and soft magnetic properties in thin films with thickness as well as annealing treatment has been systematically investigated. Fe-Si-B-P-C thin films were fabricated using radio frequency magnetron sputtering. Microstructure of as-deposited and as-annealed thin films with various thicknesses have been characterized, and corresponding soft magnetic properties have been studied. The magnetic domain structure in thin films was further characterized via the magneto-optical Kerr microscope. It is revealed that all these as-deposited thin films exhibit a columnar structure, and the surface roughening is in accordance with the anomalous scaling. The coercivity gradually decreases from 4.8 Oe for 61 nm-thick film to 0.6 Oe for 608 nm-thick film, and almost remains constant with further increasing thickness, while the magnetic impedance ratio rises with thickness. After 473 K-annealing treatment coercivity decreases and magnetic impedance ratio increases, which can be attributed to the release of residual stress and the enhanced exchange coupling. After annealing at 573 K, although no obvious improvement in coercivity occurs, magnetic impedance ratio further rises due to the enhanced electrical conductivity and the reduced magnetic anisotropy. Severe crystallization takes place after annealed at 673 K, deteriorating soft magnetic properties of thin films. Therefore, the 573 K-annealed Fe-Si-B-P-C thin film with 1210 nm in thickness exhibits the best soft magnetic properties, having coercivity of 0.3 Oe, magnetic impedance ratio of 66.2% and relatively low magnetic anisotropy, which is a very promising soft magnetic material for sensor application.

Deformation mode transition (DMT) from highly-localized to non-localized in amorphous alloy thin films (AATFs) was expected to depend on the homologous temperature. Here, DMT in Mg-Zn-Ca AATF with high homologous temperature but intrinsic brittleness was monitored during film/substrate co-bending, and its critical size for DMT is much low compared to other compositions. Intrinsically brittle nature of Mg-based AATF that facilitates the shear band to unstable crack transition may be responsible for unexpected low critical size despite of high homologous temperature.

The stability of high-entropy alloys (HEAs) is a key issue before their selection for industrial applications. In this study, in-situ high-pressure and high-temperature synchrotron radiation X-ray diffraction experiments have been performed on three typical HEAs Ni20Co20Fe20Mn20Cr20, Hf25Nb25Zr25Ti25, and Re25Ru25Co25Fe25 (at. %), having face-centered cubic (fcc), body-centered cubic (bcc), and hexagonal close-packed (hcp) crystal structures, respectively, up to the pressure of ∼80 GPa and temperature of ∼1262 K. Under the extreme conditions of the pressure and temperature, all three studied HEAs remain stable up to the maximum pressure and temperatures achieved. For these three types of studied HEAs, the pressure-dependence of the volume can be well described with the third order Birch-Murnaghan equation of state. The bulk modulus and its pressure derivative are found to be 88.3 GPa and 4 for bcc-Hf25Nb25Zr25Ti25, 193.9 GPa and 5.9 for fcc-Ni20Co20Fe20Mn20Cr20, and 304.6 GPa and 3.8 for hcp-Re25Ru25Co25Fe25 HEAs, respectively. The thermal expansion coefficient for the three studied HEAs is found to be in the order as follows: fcc-Ni20Co20Fe20Mn20Cr20 > bcc-Hf25Nb25Zr25Ti25 ≈ hcp-Re25Ru25Co25Fe25.

The effects of film thickness on structure and magnetic property of Fe-Y-B were investigated systematically. The 283nm-thick film was in fully amorphous state, and nanocrystals gradually appeared in the amorphous matrix with increasing thickness. Local roughness at small length scale also rose, indicating the anomalous growth mode. Meanwhile, soft magnetic property and magneto-impedance (MI) effect were significantly enhanced as the film thickness was initially increased. The appearance of nanograins in the soft magnetic matrix may lead to “exchange averaging of the magnetic anisotropy”, decreasing the coercivity and increasing both electrical conductivity and magnetic permeability, which can lessen the skin depth with the increasing thickness and result in the improved MI effect. As the deposition time was further prolonged, MI sensitivity remained almost unchanged in the thicker films, while MI ratio further increased, indicating that MI sensitivity relied more on the coercivity and electrical conductivity, and MI ratio on magnetic permeability and the ratio of skin depth to film thickness, since both the coercivity and electrical conductivity approach the saturated ranges and magnetic permeability continuously increased with thickness.

The effect of substrate temperature on the structure and properties of magnetron sputtered Zr–Cu–Ni–Al–Hf–Ti thin films were systematically investigated. With increasing deposition temperature from 293K to 493K, the films remain amorphous but their thermal stability decreases. Crystallization occurs as the substrate temperature reaches 563K. It was demonstrated that the hardness and Young's modulus of glassy films were enhanced and fracture toughness was worsen by increasing the substrate temperature, along with generating a denser structure. Through the scaling analysis, it was revealed that all glassy films grow in an anomalous mode. These metallic glass films prepared herein exhibit extremely low roughness, less than 1nm, high thermal stability and excellent mechanical properties, which are useful properties for their potential use for MEMS and other industry applications.

The dependence of shear yield strain, the activation energy and volume of shear transformation zone on the glass transition temperature was investigated through the analysis of statistical distributions of the first pop-in events during spherical indentation of four different thin film metallic glasses. Only the Cu–Zr metallic glass exhibits a bimodal distribution of the first pop-in loads, whereas W–Ru–B, Zr–Cu–Ni–Al and La–Co–Al metallic glasses show an unimodal distribution. Results show that shear yield strain and activation energy of shear transformation zone decrease whereas the volume of shear transformation zone increases with increasing homologous temperature, indicating that it is the activation energy rather than the volume of shear transformation zone that controls shear yield strain.

The size effect on the bending deformation behaviour of magnetron-sputtered La57Al25Co18, Cu50Zr50 and Fe70Y8B22 glassy films was investigated. The transition of the deformation mode from highly localized to non-localized occurs as the film thickness reduces below the critical value, which does not exhibit a distinct dependence on Poisson's ratio. By combining the already-reported critical size for deformation mode transition in various metallic glasses, it is found that the critical size is primarily proportional to the homologous temperature. (C) 2014 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Amorphous Fe-Y-B thin films have been successfully fabricated by direct-current magnetron sputtering, and the effects of annealing treatment on the microstructure and magnetic properties, especially coercivity and magneto-impedance ratio, were investigated systematically. After low-temperature heat treatments (below 673 K), films still remain amorphous structure and their magnetic properties were largely enhanced due to stress release, e. g., the maximum magneto-impedance ratio increases from about 5.6-46.6% and the coercivity decreases from about 7.7-2.2 Oe for as-deposited film and the film annealed at 573 K for 1 h, respectively. After high-temperature heat treatment at 673 K, crystallization occurs, deteriorating magnetic properties (magnetic softness and magneto-impedance features) of the film. The Fe-Y-B thin film annealed at 573 K for 1 h, possessing good magneto-impedance effect and soft magnetic properties, might have potential application in micro-sized magnetic actuators. (C) 2014 Elsevier B.V. All rights reserved.

Thin film metallic glasses (TFMGs) with a composition of Ni60Nb40 were magnetron sputtered on the substrate of austenitic stainless steel (SS). Potentiodynamic polarization measurements on TFMGs with different thicknesses in NaCl solution were conducted, and better corrosion resistance is achievable by increasing the film thickness. However, a critical film thickness exists, above which anti-pitting property cannot be significantly improved. The film density as a function of thickness has a similar tendency with the corrosion resistance, indicating the correlation of film density and corrosion resistance. Fossettes in the pits were observed in TFMGs deposited on SS rather than the bare SS, since pitting nuclei in TFMG can propagate more rapidly along depth than width due to the stronger pitting susceptibility of SS.