Search

The contradiction between high piezoelectricity and uniquely poor temperature stability generated by polymorphic phase boundary is a huge obstacle to high-performance (K, Na)NbO3 -based ceramics entering the application market as Pb-based substitutes. We possess the phase boundary by mimicking Pb(Zr, Ti)O3's morphotropic phase boundary structure via the synergistic optimization of diffusion phase boundary and crystal orientation in 0.94(Na0.56K0.44)NbO3−0.03Bi0.5Na0.5ZrO3−0.03(Bi0.5K0.5)HfO3 textured ceramics. As a result, a prominent comprehensive performance is obtained, including giant d33 of 550 ± 30 pC/N and ultrahigh temperature stability (d33 change rate less than 1.2% within 25-150 °C), representing a significant breakthrough in lead-free piezoceramics, even surpassing the Pb-based piezoelectric ceramics. Within the same temperature range, the d33 change rate of the commercial Pb(Zr, Ti)O3−5 ceramics is only about 10%, and more importantly, its d33 (~ 350 pC/N) is much lower than that of the (K, Na)NbO3-based ceramics in this work. This study demonstrates a strategy for constructing the phase boundary with MPB feature, settling the problem of temperature instability in (K, Na)NbO3-based ceramics. The authors induce a phase boundary similar to Pb(Zr, Ti)O3's morphotropic phase boundary structure in (K, Na)NbO3-based ceramics, which exhibit high residual polarization as well as a significantly improved piezoelectric constant d33. [ABSTRACT FROM AUTHOR]

Recent advancements in machine learning (ML) have revolutionized the field of high-performance materials design. However, developing robust ML models to decipher intricate structure-property relationships in materials remains challenging, primarily due to the limited availability of labeled datasets with well-characterized crystal structures. This is particularly pronounced in materials where functional properties are closely intertwined with their crystallographic symmetry. We introduce a self-supervised probabilistic model (SSPM) that autonomously learns unbiased atomic representations and the likelihood of compounds with given crystal structures, utilizing solely the existing crystal structure data from materials databases. SSPM significantly enhances the performance of downstream ML models by efficient atomic representations and accurately captures the probabilistic relationships between composition and crystal structure. We showcase SSPM's capability by discovering shape memory alloys (SMAs). Amongst the top 50 predictions, 23 have been confirmed as SMAs either experimentally or theoretically, and a previously unknown SMA candidate, MgAu, has been identified. [ABSTRACT FROM AUTHOR]

Mo is a key solid solution strengthening element that improves the mechanical properties of Ni-based superalloys, but the partitioning behavior of Mo remains controversial. Herein, we uncover the effect of Mo addition on the precipitation kinetics of the γ′ phase in Ni–(17−x) Al–x Mo at.% (x = 2, 3, 4, and 5) alloys by directly coupling accurate thermodynamic and kinetic descriptions with a phase-field model. Our simulations show that the addition of Mo would decrease the γ′ coarsening rate due to the decrease in the diffusion rate and the γ/γ′ lattice misfit. Besides, the partitioning behavior of Mo is reversed from the γ′ phase ( K Mo γ ′ / γ > 1 ) into the γ matrix ( K Mo γ ′ / γ < 1 ) with increasing Mo concentration, which is attributed to the solubility limit of Mo in the γ′ phase as well as a decrease in the γ/γ′ lattice misfit. Meanwhile, Al and Mo preferentially occupy the Al sublattice site of the γ′–Ni3Al and form the Ni3(Al, Mo) phase in Ni–Al–Mo ternary model alloys. Furthermore, the solid solution strengthening effect increases with increasing Mo concentration because of an increase in the Mo concentration in the γ matrix. Our results provide valuable insights into understanding the effect of Mo addition to Ni-based superalloys on the coarsening kinetics of γ′ phase and elemental partitioning behavior. [ABSTRACT FROM AUTHOR]

PbSe-based thermoelectric materials exhibit promising ZT values at medium temperature, but its near-room-temperature thermoelectric properties are overlooked, thus restricting its average ZT (ZTave) value at low-medium temperatures. Here, a high ZTave of 0.90 at low temperature (300–573 K) is reported in n-type PbSe-based thermoelectric material (Pb1.02Se0.72Te0.20S0.08−0.3%Cu), resulting in a large ZTave of 0.96 at low-medium temperatures (300–773 K). This high thermoelectric performance stems from its ultralow lattice thermal conductivity caused by dense dislocations through heavy Te/S alloying and Cu interstitial doping. The dislocation density evaluated by modified Williamson-Hall method reaches up to 5.4 × 1016 m−2 in Pb1.02Se0.72Te0.20S0.08−0.3%Cu. Moreover, the microstructure observation further uncloses two kinds of dislocations, namely screw and edge dislocations, with several to hundreds of nanometers scale in length. These dislocations in lattice can strongly intensify phonon scattering to minimize the lattice thermal conductivity and simultaneously maintain high carrier transport. As a result, with the reduced lattice thermal conductivity and optimized power factor in Pb1.02Se0.72Te0.20S0.08−0.3%Cu, its near-room-temperature thermoelectric performance is largely enhanced and exceeds previous PbSe-based thermoelectric materials. Thermoelectric material is capable of realizing direct conversion between heat and electricity. Here, the authors obtain high thermoelectric performance in PbSe at low-medium temperatures by importing dense dislocations. [ABSTRACT FROM AUTHOR]

Under the background of the rapid development of the modern electronics industry, higher requirements are put forward for the performance of energy storage ceramics such as higher energy storage density, shorter discharge time and better stability. In this study, a comprehensive driving strategy is proposed to drive the grain size of ceramic materials to the submicron level and significantly reduce their remanent polarization intensity. A new lead-free ceramic system (1 − x) K0.5Na0.5NbO3–xBiMg0.5Ti0.5O3 was prepared by the solid-state method. The effects of BMT on ceramic structure, phase transformation and energy storage properties were studied. With the introduction of BMT, the phase structure of samples changes from ortho-phase to pseudo-cubic phase with the increase in relaxation states. When x = 0.10, the energy storage properties of KNN ceramics are significantly improved, the energy storage density (W) is 3.14 J/cm3, and η is 84%. Moreover, the 0.90KNN-0.10BMT ceramic completes the discharge within 1.78 μs, and the power density (PD) is 16.3 MW/cm3 under 140 kV/cm. These excellent characteristics make 0.90KNN-0.10BMT which becomes a kind of lead-free pulse ceramic material with great potential. [ABSTRACT FROM AUTHOR]

Metals with nanocrystalline grains have ultrahigh strengths approaching two gigapascals. However, such extreme grain-boundary strengthening results in the loss of almost all tensile ductility, even when the metal has a face-centred-cubic structure—the most ductile of all crystal structures1–3. Here we demonstrate that nanocrystalline nickel–cobalt solid solutions, although still a face-centred-cubic single phase, show tensile strengths of about 2.3 gigapascals with a respectable ductility of about 16 per cent elongation to failure. This unusual combination of tensile strength and ductility is achieved by compositional undulation in a highly concentrated solid solution. The undulation renders the stacking fault energy and the lattice strains spatially varying over length scales in the range of one to ten nanometres, such that the motion of dislocations is thus significantly affected. The motion of dislocations becomes sluggish, promoting their interaction, interlocking and accumulation, despite the severely limited space inside the nanocrystalline grains. As a result, the flow stress is increased, and the dislocation storage is promoted at the same time, which increases the strain hardening and hence the ductility. Meanwhile, the segment detrapping along the dislocation line entails a small activation volume and hence an increased strain-rate sensitivity, which also stabilizes the tensile flow. As such, an undulating landscape resisting dislocation propagation provides a strengthening mechanism that preserves tensile ductility at high flow stresses.A nanocrystalline metallic alloy with ultrahigh tensile strength and good ductility is achieved by introducing compositional undulation in a highly concentrated solid solution. [ABSTRACT FROM AUTHOR]

Two-dimensional materials with ferroelectric properties break the size effect of conventional ferroelectric materials and unlock unprecedented potentials of ferroelectric-related application at small length scales. Using first-principles calculations, a sliding-induced ferroelectric-to-antiferroelectric behavior in bilayer group-IV monochalcogenides (MX, with M = Ge, Sn and X = S, Se) is discovered. Upon this mechanism, the top layer exhibits a reversible intralayer ferroelectric switching, leading to a reversible transition between the ferroelectric and antiferroelectric states in the bilayer MXs. Further results show that the interlayer van der Waals interaction, which is usually considered to be weak, can actually generate an in-plane lattice distortion and thus cause the breaking/forming of intralayer covalent bonds in the top layer, leading to the observed anomalous phenomenon. This unique property has advantages for energy harvesting over existing piezoelectric and triboelectric nanogenerators. The interlayer sliding-induced big polarization change (40 μC cm−2) and ultrahigh polarization changing rate generate an open-circuit voltage two orders of magnitude higher than that of MoS2-based nanogenerators. The theoretical prediction of power output for this bilayer MXs at a moderate sliding speed 1 m s−1 is four orders of magnitude higher than the MoS2 nanogenerator, indicating great potentials in energy harvesting applications. [ABSTRACT FROM AUTHOR]

The microstructural evolution of Mg–2.0Gd–1.2Y–1.0Zn–0.2Zr (GWZK) alloy during homogenization and subsequent aging heat-treatment and the tensile properties of the peak-aged sample at various temperatures have been investigated. The phase transformation during homogenization, static precipitation during aging, and deformation mechanisms at 250 °C are systematically analyzed through XRD, TEM and EBSD measurements. The peak-aged GWZK alloy has good combination of strength and ductility at elevated temperatures owing to its high thermal stability by the LPSO phases distributed along the grain boundaries. The change (19 MPa) in the yield strength of peak-aged samples between RT and 250 °C is mainly related to easy gliding of dislocations on the non-basal planes due to the decrease in critical resolved shear stress of slip. Two strengthening models are applied to quantitatively describe the effect of 11 2 - 0 α precipitate plates on Orowan strengthening corresponding to RT and 250 °C. Ignoring changes in solid solution strengthening and grain boundary strengthening of the peak-aged sample caused by increasing temperature, the calculated reduction value (16.5 MPa) in macroscopic yield strength from RT (based on the basal < a > slip mode) to 250 °C (based on the pyramidal < c + a > slip mode) is in good agreement with the measured reduction value (19 MPa). [ABSTRACT FROM AUTHOR]

Multitudinous topological configurations spawn oases of many physical properties and phenomena in condensed-matter physics. Nano-sized ferroelectric bubble domains with various polar topologies (e.g., vortices, skyrmions) achieved in ferroelectric films present great potential for valuable physical properties. However, experimentally manipulating bubble domains has remained elusive especially in the bulk form. Here, in any bulk material, we achieve self-confined bubble domains with multiple polar topologies in bulk Bi0.5Na0.5TiO3 ferroelectrics, especially skyrmions, as validated by direct Z-contrast imaging. This phenomenon is driven by the interplay of bulk, elastic and electrostatic energies of coexisting modulated phases with strong and weak spontaneous polarizations. We demonstrate reversable and tip-voltage magnitude/time-dependent donut-like domain morphology evolution towards continuously and reversibly modulated high-density nonvolatile ferroelectric memories. Experimentally manipulating bubble domains remains elusive especially in the bulk form of ferroelectrics. Here, the authors achieve self-confined bubble domains with multiple polar topologies in bulk Bi0.5Na0.5TiO3 ferroelectrics, demonstrating reversible and donut-like domain morphology evolution. [ABSTRACT FROM AUTHOR]

Lateral heterostructures of two-dimensional (2D) materials, integrating different phases or materials into a single piece of nanosheet, have attracted intensive research interests for electronic devices. Extending the 2D lateral heterostructures to spintronics demands more diverse electromagnetic properties of 2D materials. In this paper, using density functional theory calculations, we survey all IV, V, and VI group transition metal dichalcogenides (TMDs) and discover that CrS2 has the most diverse electronic and magnetic properties: antiferromagnetic (AFM) metallic 1T phase, non-magnetic (NM) semiconductor 2H phase, and ferromagnetic (FM) semiconductor 1T′ phase with a Curie temperature of ~1000 K. Interestingly, we find that a tensile or compressive strain can turn the 1T′ phase into a spin-up or spin-down half-metal. Such strain tunability can be attributed to the lattice deformation under tensile/compressive strain that selectively promotes the spin-up/spin-down VBM (valence band bottom) orbital interactions. The diverse electromagnetic properties and the strain tunability enable strain-controlled spintronic devices using a single piece of CrS2 nanosheet with improved energy efficiency. As a demo, a prototypical design of the spin-valve logic device is presented. It offers a promising solution to address the challenge of high energy consumption in miniaturized spintronic devices. [ABSTRACT FROM AUTHOR]

Traditional strategies for improving piezoelectric properties have focused on phase boundary engineering through complex chemical alloying and phase control. Although they have been successfully employed in bulk materials, they have not been effective in thin films due to the severe deterioration in epitaxy, which is critical to film properties. Contending with the opposing effects of alloying and epitaxy in thin films has been a long-standing issue. Herein we demonstrate a new strategy in alkali niobate epitaxial films, utilizing alkali vacancies without alloying to form nanopillars enclosed with out-of-phase boundaries that can give rise to a giant electromechanical response. Both atomically resolved polarization mapping and phase field simulations show that the boundaries are strained and charged, manifesting as head-head and tail-tail polarization bound charges. Such charged boundaries produce a giant local depolarization field, which facilitates a steady polarization rotation between the matrix and nanopillars. The local elastic strain and charge manipulation at out-of-phase boundaries, demonstrated here, can be used as an effective pathway to obtain large electromechanical response with good temperature stability in similar perovskite oxides. Phase boundary engineering through chemical alloying and phase control is a traditional approach to enhancing piezoelectric properties. Here, the authors design a strategy in alkali niobate films, utilizing alkali vacancies without alloying to form nanopillars enclosed. [ABSTRACT FROM AUTHOR]

Excellent energy storage performance of dielectric capacitors is highly desired in all kinds of energy storage devices. In this study, Sr(Sc0.5Nb0.5)O3 was introduced to enhance the energy storage properties of (Bi0.47La0.03Na0.5)0.94Ba0.06TiO3 (BLNBT) ceramics. All ceramic samples were sintered densely, and the phase structure, microstructure, dielectric and ferroelectric properties were then systematically investigated. Two distinct dielectric anomaly peaks, which are detected from the dielectric properties as a function of temperature, suggest not only a phase transition, but also indicate typical relaxor features. The breakdown strength is significantly improved, and the polarization versus electric field hysteresis loops become slim with the increasing content of SSN. The optimum energy storage performance is achieved in 0.85BLNBT–0.15SSN ceramic with the recoverable energy density of 1.83 J/cm3 and energy efficiency of 82.32% under a moderate electric field of 185 kV/cm. The excellent energy storage performance of 0.85BLNBT–0.15SSN ceramic makes it a promising candidate material for advanced pulsed power capacitors. [ABSTRACT FROM AUTHOR]

In this study, the high-speed impact behavior and microstructure evolution of an extruded Mg-7Sn-5Zn-3Al alloy were investigated under different strain rates (1626-4126 s−1) using a Split Hopkinson pressure bar. The experimental results indicated that the number of twins and dynamic recrystallization (DRX) increased, while the average grain size of the extruded alloy continuously decreased with the increase in the strain rates. In addition, the texture type of the extruded alloy transformed from (0001) <10-10> to (11-20) <0001> during impacts. The high-speed impact behavior of the extruded alloy was found to strongly depend on the strain rate at room temperature. The strain rate sensitivity (SRS) changed from positive to negative with the increase in the strain rate. The negative SRS was mainly attributed to the DRX and the formation of micro-cracks at high strain rates (3712 s−1< ε ˙ < 4126 s−1). In addition, the elongation to failure (δ ) and yield strength ( σ 0.2 ) of the extruded alloy increased, while the maximum strength ( σ max ) exhibited a nonlinear trend with the increase in the strain rates. The improved mechanical properties mainly originated from the grain refinement and texture strengthening. Multicrack propagation and intergranular quasi-cleavage fracture were the main dynamic fracture mechanisms of the extruded alloy during impacts. [ABSTRACT FROM AUTHOR]

In this work, we use the finite element method to investigate the free volume evolution, as well as the martensite transformation effect and its connection with the pretreatment strain, in a shape memory alloy-metallic glass composite. Our simulation results show that the martensite phase transformation can enhance the blocking effect while relieving the free volume localization. The synergistic effect among the martensite transformation effect, blocking effect, and shear band interaction in the composite is responsible for the tensile plasticity and work-hardening capability. In addition, we design a Sierpinski carpet-like fractal microstructure so that the composite exhibits improved tensile performance as a result of the enhanced synergistic effect. However, the tensile performance of the composite deteriorates with increasing pretreatment strain since the martensite transformation effect is weakened. [ABSTRACT FROM AUTHOR]

A continuous martensite transformation is indispensable for achieving large linear superelasticity and low modulus in phase transforming metal-based composites. However, determining how to accurately condition the residual martensite in a shape memory alloy matrix though the reinforcement shape to achieve continuous martensite transformation has been a challenge. Here, we take the finite element method to perform a comparative study of the effects of nanoinclusion shape on the interaction and martensite phase transformation in this new composite. Two typical samples are compared: one reinforced by metallic nanowires and the other by nanoparticles. We find that the residual martensite within the shape memory alloy matrix after a pretreatment can be tailored by the reinforcement shape. In particular, our results show that the shape memory alloy matrix can retain enough residual martensite phases to achieve continuous martensite transformation in the subsequent loading when the aspect ratio of nanoreinforcement is larger than 20. In contrast, the composites reinforced with spherical or low aspect ratio reinforcement show a typical nonlinear superelasticity as a result of a low stress transfer-induced discontinuous martensite transformation within the shape memory alloy matrix. [ABSTRACT FROM AUTHOR]

Correction to: I Nature Communications i https://doi.org/10.1038/s41467-022-34062-6, published online 25 October 2022 In this article the affiliation 'Institute of Materials Research and Engineering, Agency for Science, Technology and Research (A*STAR), Singapore, Singapore'. for Jie Yin should be removed. The affiliation 'Institute of Materials Research and Engineering, Agency for Science, Technology and Research (A*STAR), Singapore, Singapore' for Kui Yao should read "Institute of Materials Research and Engineering, Agency for Science, Technology and Research (A*STAR), Singapore 138634, Singapore". [Extracted from the article]

Graphite and other lamellar materials are used as dry lubricants for macroscale metallic sliding components and high-pressure contacts. It has been shown experimentally that monolayer graphene exhibits higher friction than multilayer graphene and graphite, and that this friction increases with continued sliding, but the mechanism behind this remains subject to debate. It has long been conjectured that the true contact area between two rough bodies controls interfacial friction. The true contact area, defined for example by the number of atoms within the range of interatomic forces, is difficult to visualize directly but characterizes the quantity of contact. However, there is emerging evidence that, for a given pair of materials, the quality of the contact can change, and that this can also strongly affect interfacial friction. Recently, it has been found that the frictional behaviour of two-dimensional materials exhibits traits unlike those of conventional bulk materials. This includes the abovementioned finding that for few-layer two-dimensional materials the static friction force gradually strengthens for a few initial atomic periods before reaching a constant value. Such transient behaviour, and the associated enhancement of steady-state friction, diminishes as the number of two-dimensional layers increases, and was observed only when the two-dimensional material was loosely adhering to a substrate. This layer-dependent transient phenomenon has not been captured by any simulations. Here, using atomistic simulations, we reproduce the experimental observations of layer-dependent friction and transient frictional strengthening on graphene. Atomic force analysis reveals that the evolution of static friction is a manifestation of the natural tendency for thinner and less-constrained graphene to re-adjust its configuration as a direct consequence of its greater flexibility. That is, the tip atoms become more strongly pinned, and show greater synchrony in their stick-slip behaviour. While the quantity of atomic-scale contacts (true contact area) evolves, the quality (in this case, the local pinning state of individual atoms and the overall commensurability) also evolves in frictional sliding on graphene. Moreover, the effects can be tuned by pre-wrinkling. The evolving contact quality is critical for explaining the time-dependent friction of configurationally flexible interfaces. [ABSTRACT FROM AUTHOR]

The interferon regulatory factor 9 ( IRF9) gene is a member of the IRF family and has been shown to play functionally diverse roles in the regulation of the immune system. Previous study revealed the IRF9 gene resides within the reported quantitative trait locus (QTLs) for cytokine levels. The aims of this study were to identify genomic variants in IRF9 and to test the association between the variants and cytokine levels in pig. A synonymous single-nucleotide polymorphism ( c.459A > G) was identified in exon 4 of the IRF9 gene. Association analysis in 300 piglets (Landrace, n = 68; large white, n = 158; and Songliao black, n = 74) showed that this variant was significantly associated with the level of interferon (IFN)-γ and the ratio of IFN-γ to IL-10 in serum ( P < 0.05). Relative quantification of messenger RNA (mRNA) revealed that spleen had the highest expression level and individuals with genotype AA had higher expression than those with genotype AG. Transfection-based mRNA stability assay analysis further showed that the mutant allele G could reduce the RNA stability of IRF9. These findings suggest that the SNP ( c.459A > G) could be a causative mutation for the association between IRF9 and the serum cytokine levels in swine. [ABSTRACT FROM AUTHOR]

Findings from previous studies suggested that the cluster of the differentiation 8 alpha ( CD8A) gene plays a prominent role in human T lymphocyte subpopulations. However, the evidence from pig population is still rare. To determine whether the important role of the CD8A gene is conserved in pig, a candidate gene analysis was performed herein through genotype-phenotype associations. Five single-nucleotide polymorphisms (SNPs) locating in the regulatory region of porcine CD8A gene were detected and tested for association analysis with seven T lymphocyte subpopulations (proportion of CD4CD8, CD4CD8, CD4CD8, CD4CD8, CD4, CD8, and the ratio of CD4 to CD8 T cells in peripheral blood) in 382 Large White piglets. After Bonferroni correction for multiple testing, four SNPs were significantly associated with some or all of the seven T lymphocyte subpopulations. Analyses of pairwise D' measures of linkage disequilibrium between all SNPs were also explored. Two haplotype blocks was inferred and the association study on haplotype level revealed similar effects on T lymphocyte subpopulations. In addition, the tissue-specific RNA expression pattern and electrophoretic mobility shift assay offered further explanation of the link between the CD8A gene with porcine T lymphocyte subpopulations. The findings presented here provide strong evidence for associations of CD8A variants with T lymphocyte subpopulations and may be applied in porcine breeding programs. [ABSTRACT FROM AUTHOR]

General pedigrees are very common in farm animals, and the recent availability of large panels of SNPs in domestic species has given new momentum to the search for the mutations underlying variation in quantitative traits. In this paper, we proposed a new transmission disequilibrium test approach, called the pedigree transmission disequilibrium test, which deals with general pedigrees and quantitative traits in farm animals. Compared with the existing pedigree disequilibrium test (PDT) and general linear model-based method QTDT, our approach performed better with higher power and lower type I error, especially in scenarios where the quantitative trait locus (QTL) effect was small. We also investigated the application of our approach in selective genotyping design. Our simulation studies indicated that it was plausible to implement a selective genotyping strategy in the proposed pedigree transmission disequilibrium test. We found that our approach performed equally well or better when only some proportion of the individuals in the two tails were genotyped compared with its performance when all the individuals in the pedigree were genotyped. [ABSTRACT FROM AUTHOR]

Genomic selection (GS) is a marker-assisted selection method, in which high density markers covering the whole genome are used simultaneously for individual genetic evaluation via genomic estimated breeding values (GEBVs). GS can increase the accuracy of selection, shorten the generation interval by selecting individuals at the early stage of life, and accelerate genetic progress. With the availability of high density whole genome SNP (single nucleotide polymorphism) chips for livestock, GS is reshaping the conventional animal breeding systems. In many countries, GS is becoming the major genetic evaluation method for bull selection in dairy cattle and GS may soon completely replace the traditional genetic evaluation system. In recent years, GS has become an important research topic in animal, plant and aquiculture breeding and many exciting results have been reported. In this paper, the methods for obtaining GEBVs, factors affecting the accuracy of GEBVs, and the current status of implementation of GS in livestock are reviewed. Some unresolved issues related to GS in livestock are also discussed. [ABSTRACT FROM AUTHOR]

Flexible, large area electronics using various organic and inorganic materials are beginning to show great promise. During manufacture and service, large deformation of these hybrid materials will pose significant challenges in terms of high performance and reliability. A deep understanding of the ductility or flexibility of macroelectronics becomes one of the major issues that must be addressed urgently. This paper describes the current level of understanding on the thin-film ductility, both free-standing and substrate-supported, and relevant influencing factors. [ABSTRACT FROM AUTHOR]

With biological and economic importance, threshold traits are discrete in phenotype but have the same polygenic genetic basis as quantitative traits. The traditional linkage analysis for quantitative traits is invalid for threshold traits due to their special characters. The transmission disequilibrium test (TDT) has received great attention recently in localizing human disease genes due to its simplicity and powerfulness. But TDT only deals with data from independent nuclear families and it will lose information about extended pedigree that incorporates information not only from parents and siblings but also from other relatives. The pedigree disequilibrium test (PDT) proposed by Martin in 2001 can be used to analyze the extended pedigree in human. In this study, POT was introduced into the QTL mapping of threshold traits for farm animals, and was modified in order to accommodate the pedigree structures of farm animals. The modified PDT was renamed pedigree transmission disequilibrium test (PTDT) and its power and type I error were investigated and compared with that of POT by Monte Carlo simulation. It was shown that PTDT is a robust and valid approach to mapping QTL of threshold trail When the parental information is complete, PTDT and PDT are almost the same in terms of power and type I error. However, if the parental information is missing to a certain extent, PTDT is higher in power and lower in type I error than PDT. These results imply that PTDT can be a novel approach to QTL fine mapping of threshold traits based on the existing coarse mapping information. [ABSTRACT FROM AUTHOR]

These authors contributed equally: Jie Yin, Hongxiang Zong Correction to: I Nature Communications i https://doi.org/10.1038/s41467-021-23863-w; published online 15 June 2021 The original version of this Article misspelled the following number in the Acknowledgements: '52032007', which incorrectly read '52032007, 52032007'. This has now been corrected in both the PDF and HTML versions of the Article. [Extracted from the article]

Ferroelastic twin boundaries often have properties that do not exist in bulk, such as superconductivity, polarity etc. Designing and optimizing domain walls can hence functionalize ferroelastic materials. Using atomistic simulations, we report that moving domain walls have magnetic properties even when there is no magnetic element in the material. The origin of a robust magnetic signal lies in polar vortex structures induced by moving domain walls, e.g., near the tips of needle domains and near domain wall kinks. These vortices generate displacement currents, which are the origin of magnetic moments perpendicular to the vortex plane. This phenomenon is universal for ionic crystals and holds for all ferroelastic domain boundaries containing dipolar moments. The magnetic moment depends on the speed of the domain boundary, which can reach the speed of sound under strong mechanical forcing. We estimate that the magnetic moment can reach several tens of Bohr magnetons for a collective thin film of 1000 lattice planes and movements of the vortex by the speed of sound. The predicted magnetic fields in thin slabs are much larger than those observed experimentally in SrTiO3/LaAlO3 heterostructures, which may be due to weak (accidental) forcing and slow changes of the domain patterns during their experiments. The dynamical multiferroic properties of ferroelastic domain walls may have the potential to be used to construct localized magnetic memory devices in future. [ABSTRACT FROM AUTHOR]

Electric switching of non-polar bulk crystals is shown to occur when domain walls are polar in ferroelastic materials and when rough surfaces with steps on an atomic scale promote domain switching. All domains emerging from surface nuclei possess polar domain walls. The progression of domains is then driven by the interaction of the electric field with the polarity of domain boundaries. In contrast, smooth surfaces with higher activation barriers prohibit effective domain nucleation. We demonstrate the existence of an electrically driven ferroelectric hysteresis loop in a non-ferroelectric, ferroelastic bulk material. [ABSTRACT FROM AUTHOR]

We identified heterogeneous Mg-Ho alloys as an ideal material to measure the most extensive acoustic emission spectra available. Mg-Ho alloys are porous and show a high density of dislocations, which slide under external tension and compression. These dislocations nucleate near numerous heterogeneities. Two mechanisms compete under external forcing in the structural collapse, namely collapsing holes and the movements of dislocations. Their respective fingerprints in acoustic emission (AE) measurements are very different and relate to their individual signal strengths. Porous collapse generates very strong AE signals while dislocation movements create more but weaker AE signals. This allows the separation of the two processes even though they almost always coincide temporarily. The porous collapse follows approximately mean-field behavior (ε = 1.4, τ' = 1.82, α = 2.56, x = 1.93, χ = 1.95) with mean field scaling fulfilled. The exponents for dislocation movement are greater (ε = 1.92, τ' = 2.44, α = 3.0, x = 1.7, χ = 1.42) and follows approximately the force integrated mean-field predictions. The Omori scaling is similar for both mechanisms. The Bath's law is well fulfilled for the porous collapse but not for the dislocation movements. We suggest that such 'complex' mixing behavior is dominant in many other complex materials such as (multi-) ferroics, entropic alloys and porous ferroelastics, and, potentially, homogeneous materials with the simultaneous appearance of different collapse mechanisms. [ABSTRACT FROM AUTHOR]

Atomic simulations provide an effective means to understand the underlying physics of structural phase transformations. However, this remains a challenge for certain allotropic metals due to the failure of classical interatomic potentials to represent the multitude of bonding. Based on machine-learning (ML) techniques, we develop a hybrid method in which interatomic potentials describing martensitic transformations can be learned with a high degree of fidelity from ab initio molecular dynamics simulations (AIMD). Using zirconium as a model system, for which an adequate semiempirical potential describing the phase transformation process is lacking, we demonstrate the feasibility and effectiveness of our approach. Specifically, the ML-AIMD interatomic potential correctly captures the energetics and structural transformation properties of zirconium as compared to experimental and density-functional data for phonons, elastic constants, as well as stacking fault energies. Molecular dynamics simulations successfully reproduce the transformation mechanisms and reasonably map out the pressure–temperature phase diagram of zirconium. Interatomic potentials: predicting phase transformations in zirconium Machine learning leads to a new interatomic potential for zirconium that can predict phase transformations. A team led by Hongxian Zong at Xi'an Jiaotong University, China, and Turab Lookman at Los Alamos National Laboratory, U.S.A, used a Gaussian-type machine learning approach to produce an interatomic potential that predicted phase transformations in zirconium. They expressed each atomic energy contribution via changes in the local atomic environment, such as bond length, shape, and volume. The resulting machine-learning potential successfully described pure zirconium's physical properties. When used in molecular dynamics simulations, it predicted a zirconium phase diagram as a function of both temperature and pressure that agreed well with previous experiments and simulations. Developing learnt interatomic potentials in phase-transforming systems could help us better simulate complex systems. [ABSTRACT FROM AUTHOR]

An open question is the underlying mechanisms for a recent discovered nanocomposite, which composed of shape memory alloy (SMA) matrix with embedded metallic nanowires (NWs), demonstrating novel mechanical properties, such as large quasi-linear elastic strain, low Young's modulus and high yield strength. We use finite element simulations to investigate the interplay between the superelasticity of SMA matrix and the elastic-plastic deformation of embedded NWs. Our results show that stress transfer plays a dominated role in determining the quasi-linear behavior of the nanocomposite. The corresponding microstructure evolution indicate that the transfer is due to the coupling between plastic deformation within the NWs and martensitic transformation in the matrix, i.e., the martensitic transformation of the SMA matrix promotes local plastic deformation nearby, and the high plastic strain region of NWs retains considerable martensite in the surrounding SMA matrix, thus facilitating continues martensitic transformation in subsequent loading. Based on these findings, we propose a general criterion for achieving quasi-linear elasticity. [ABSTRACT FROM AUTHOR]

The impact of Cu doping on the martensitic transformation and shape memory properties of a high-temperature shape memory alloy system, Ti31.5Hf15Zr5Ni48.5−xCux (x = 0, 5, 10, 15, 20), was investigated. Both the martensitic transformation temperature (Ms) and the transformation enthalpy decrease monotonically with increasing Cu content x, while the recoverable strain exhibits a saddle curve with a minimum value at x = 10. These Cu content-dependent behaviors were attributed to the constraint effect caused by the different size distribution of Ti2Ni-like second phases. Additionally, a scaled linear relationship between Ms and several elemental features, including the modified valence electron concentration, electronegativity, and atomic volume, was established to describe the Cu content dependence of Ms across various Cu-containing TiNi-based systems. The experimental results presented herein, along with the proposed functional form, offer insights for the design of Cu-containing shape memory alloys.Graphical abstract: The impact of Cu doping on the martensitic transformation and shape memory properties of a high-temperature shape memory alloy system, Ti31.5Hf15Zr5Ni48.5−xCux (x = 0, 5, 10, 15, 20), was investigated. Both the martensitic transformation temperature (Ms) and the transformation enthalpy decrease monotonically with increasing Cu content x, while the recoverable strain exhibits a saddle curve with a minimum value at x = 10. These Cu content-dependent behaviors were attributed to the constraint effect caused by the different size distribution of Ti2Ni-like second phases. Additionally, a scaled linear relationship between Ms and several elemental features, including the modified valence electron concentration, electronegativity, and atomic volume, was established to describe the Cu content dependence of Ms across various Cu-containing TiNi-based systems. The experimental results presented herein, along with the proposed functional form, offer insights for the design of Cu-containing shape memory alloys. [ABSTRACT FROM AUTHOR]