Amorphous shear bands in crystalline materials as drivers of plasticity

Traditionally, the formation of amorphous shear bands (SBs) in crystalline materials has been undesirable, because SBs can nucleate voids and act as precursors to fracture. They also form as a final stage of accumulated damage. Only recently SBs were found to form in undefected crystals, where they serve as the primary driver of plasticity without nucleating voids. Here, we have discovered trends in materials properties that determine when amorphous shear bands will form and whether they will drive plasticity or lead to fracture. We have identified the materials systems that exhibit SB deformation, and by varying the composition, we were able to switch from ductile to brittle behavior. Our findings are based on a combination of experimental characterization and atomistic simulations, and they provide a potential strategy for increasing toughness of nominally brittle materials

Learning based motion artifacts processing in fNIRS: a mini review

This paper provides a concise review of learning-based motion artifacts (MA) processing methods in functional near-infrared spectroscopy (fNIRS), highlighting the challenges of maintaining optimal contact during subject movement, which can lead to MA and compromise data integrity. Traditional strategies often result in reduced reliability of the hemodynamic response and statistical power. Recognizing the limited number of studies focusing on learning-based MA removal, we examine 315 studies, identifying seven pertinent to our focus area. We discuss the current landscape of learning-based MA correction methods and highlight research gaps. Noting the absence of standard evaluation metrics for quality assessment of MA correction, we suggest a novel framework, integrating signal and model quality considerations and employing metrics like ΔSignal-to-Noise Ratio (ΔSNR), confusion matrix, and Mean Squared Error. This work aims to facilitate the application of learning-based methodologies to fNIRS and improve the accuracy and reliability of neurovascular studies

Calculation and Treatment Measures of Sulfur Dioxide Emission in Waste Gas of Ceramic Industry

The emission index of sulfur dioxide in the exhaust gas of the ceramic industry is an important indicator of the green production of enterprises and the green development of society. This article analyzes the emission sources of sulfur dioxide in the exhaust gas of the ceramic industry, and gives the calculation method for calculating the sulfur dioxide emissions in raw materials and fuels. At the same time, it compares the two-alkali wet desulfurization, limestone-gypsum wet desulfurization, and semi-dry desulfurization. The three governance measures provide references for ceramic companies to evaluate sulfur dioxide emissions and treatment

Uniaxial Negative Thermal Expansion, Negative Linear Compressibility, and Negative Poisson's Ratio Induced by Specific Topology in Zn[Au(CN)(2)](2)

The well-known idea of "structure determines properties" can be understood profoundly in the case of hexagonal zinc dicyanometalate. Using density functional theory (DFT) calculations, we show the uniaxial negative thermal expansion (NTE) and negative linear compressibility (NLC) properties of Zn[Au(CN)(2)](2). The temperature dependence of phonon frequencies within the quasi harmonic approximation (QHA) is investigated. The abnormal phonon hardening (frequency increase on heating) is detected in the ranges of 0-225, 320-345, and 410-430 cm(-1), which can be indicative of the unusual physical properties of Zn[Au(CN)(2)](2). Due to the significance of low-energy phonon frequencies in Zn[Au(CN)(2)](2), in this work, the corresponding vibrational mode of the lowest-frequency optical phonon at the zone center is analyzed. The specific topology of a springlike framework that will produce the effects of a compressed spring on heating and an extended spring under hydrostatic pressure is identified and leads to the coexistence of uniaxial-NTE and NLC behaviors in Zn[Au(CN)(2)](2). The. distinguishing phonon group velocity along the a axis and c axis facilitates different responses for both the axes under temperature and hydrostatic pressure field. Through an analysis and visualization of the spatial dependence of elastic tensors, it is found that a negative Poisson's ratio (NPR) is presented in all projection planes due to the specific topology

Enhanced thermal conductivity in off-stoichiometric La-(Fe,Co)-Si magnetocaloric alloys

A dual-phase structure consisting of the NaZn13-type (1: 13) matrix and a secondary (Fe, Co)-Si phase is designed in Fe-rich La-(Fe, Co)-Si compounds. As the extra-Fe doping altered Co content of the 1: 13 phase, the magnetic entropy change keeps to be a relatively large magnitude of 6.7-7.7 J/kgK in 265-290K for 2 T field change. In addition, mechanical properties were apparently improved by second-phase strengthening. The primary significance in this work is that the composition modification in matrix phase brings about a drastic increase in the thermal conductivity, which can be ascribed to the weakening effect of phonon point-defect-scattering. On the basis of Neilsen two-phase system model, the electrical conductivity of dispersed (Fe, Co)-Si phase plays very limited contribution to the enhanced thermal transport properties in composites. Our results demonstrate that the combined merits of high thermal conductivity, improved mechanical properties, large magnetic entropy change, and tunable transition temperature can be simultaneously realized in Fe-rich La-(Fe, Co)-Si composite materials. (C) 2015 AIP Publishing LLC

The Effects of Forming CeFe2 on Phase Structure and Magnetic Properties in Ce-Rich Nd-Ce-Fe-B Permanent Magnetic Materials

The decomposition of the Nd-Ce-Fe-B phase to form CeFe2 has been usually believed to have an important positive effect on the magnetic properties of Nd-Ce-Fe-B permanent magnetic materials. In this work, a new decomposition process of the Nd-Ce-Fe-B phase on the formation of the CeFe2 phase was observed to play a negative role in its magnetic properties. It is demonstrated that the Nd-Ce-Fe-B phase decomposes into non-magnetic CeFe2, accompanied by the precipitation of Fe soft-phase. The kinks usually occurring in the demagnetization curves of Ce-rich Nd-Ce-Fe-B magnets have been determined to be related to the Fe soft-phase. Instead of using CeFe2 as a grain-boundary phase, another Ce-Cu boundary phase has been explored to efficiently improve the coercivity of Ce-rich Nd-Ce-Fe-B magnets, provided that the Ce-Cu boundary phase has an appropriate Ce to Cu ratio. The present results contribute to the mechanism comprehension and high-performance design of Nd-Ce-Fe-B permanent magnetic materials

Plasticity without dislocations in a polycrystalline intermetallic

Plasticity without dislocations in a polycrystalline intermetalli