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Nanoscale cobalt-containing nitrogen-doped porous carbon (CoNC) materials were prepared by thermolysis of a zeolitic imidazolate framework (ZIF), ZIF-67, at different temperatures and their application for ionic electro-active polymer (EAP) actuator was evaluated. CoNC-700, which was obtained from ZIF-67 pyrolysis at 700 °C, exhibits specific surface area of 753.86 m2 g−1, pore volume of 0.5768 cm3 g−1, and specific capacitance of 120.7 F∙g−1. CoNC/conducting polymer soft electrode were fabricated by unitizing effective interaction of CoNC with poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS). High-performance ionic actuators were developed for the first time using this CoNC/PEDOT:PSS soft electrode. The developed ionic EAP actuator exhibited large peak-to-peak displacement of 20.4 mm and high bending strain of 0.28% (3 V and 0.1 Hz). Therefore, ZIFs or metal organic frameworks (MOFs) can be applied to provide significant improvements in EAP actuators, which can play key roles as technological advances toward bioinspired actuating devices required for next-generation soft and wearable electronics.

Simultaneous enhancement of strength and ductility of high entropy alloys through plastic forming and heat treatment procedures is difficult to realize. Through cold rolling and annealing on an as cast Fe24Co23Ni24Cr23Ti2Al4 high entropy alloy (HEA), the crystallographic structure transforms from a single face-centered cubic (fcc) phase to a dual body-centered cube (bcc) and fcc phases accompanied by precipitated strip shaped bcc phase with enriched Al–Ni binary structure. Based on a significant reduction in grain size from 2.87 ± 0.25 μm to 0.45 ± 0.15 μm and grain boundary type change from predominant high-angle grain boundaries to combination of predominant low-angle grain boundaries and precipitated band-shaped high-angle grain boundaries, the grain size gradient is substantially improved. The fracture mode also transforms from typical microvoid accumulation ductile fracture to ductile in-plane-shear fracture. Accordingly, the tensile strength and Vickers hardness enhance by 105.8% (from 861.2 to 418.1 MPa) and 172.8% (from 487.3 to 178.6 HV), respectively. In especial, the excellent ductility is maintained, as the elongation after fracture merely reduces from 0.22 to 0.17.

Crystallization behaviors of bulk metallic glass (BMG) have been obtaining widespread concern, especially under service conditions including elevated temperature, electrical pulse, mechanical stress and high pressure. In this paper, cyclic stress was considered as typical service condition and applied on a Zr55Cu30Al10Ni5 BMG specimen with prefabricated double V-notches. Through indentation tests on fatigue-fractured specimen along with the connection line between notch tips, diversities in indentation serrated flow behaviors and morphological anisotropies were directly observed. Through transmission electron microscopy (TEM) characterization and selected area electron diffraction (SAED) analysis of thinned BMG specimen adjacent to indentation edge, direct experimental evidence of local crystallization at room temperature (RT) was verified. Meanwhile, the distance-dependent crystallization behavior was investigated in terms of gradually increased quantity of diffraction spots and precipitated nanocrystalline adjacent to indentation edge. Furthermore, high resolution transmission electron microscopy (HRTEM) images and SAED patterns at identical indentation microregion of tensile-fractured BMG specimen did not exhibit obvious nanocrystalline and diffraction spots, which indicated that the cyclic stress rather than static stress induced surface crystallization adjacent to indentation edge at RT.

This paper shows that, counter to common perception, stock prices in China are strongly linked to firm fundamentals. Since the reforms of the early 2000s, stock prices are as informative about future profits as they are in the US. Although the market is segmented from international equity markets, Chinese investors price individual stock characteristics like other global investors: they pay up for size, growth, liquidity, and long shots, while they discount for systematic risk. Price informativeness is significantly correlated with corporate investment e ciency. For international investors, China's stock market offers high average returns and low correlation with other equity markets.