Explore the vast range of titles available.

Intermetallic alloys have traditionally been characterized by their inherent brittleness due to their lack of sufficient slip systems and absence of strain hardening. However, here we developed a single-phase B2 high-entropy intermetallic alloy that is both strong and plastic. Unlike conventional intermetallics, this high-entropy alloy features a highly distorted crystalline lattice with complex chemical order, leading to multiple slip systems and high flow stress. In addition, the alloy exhibits a dynamic hardening mechanism triggered by dislocation gliding that preserves its strength across a wide range of temperatures. As a result, this high-entropy intermetallic circumvents precipitous thermal softening, with extensive plastic flows even at high homologous temperatures, outperforming a variety of both body-centered cubic and B2 alloys. These findings reveal a promising direction for the development of intermetallic alloys with broad engineering applications. Intermetallics are traditionally characterised by their inherent brittleness due to a lack of sufficient slip systems and the absence of strain hardening. Here authors show that a single-phase distorted high entropy B2 intermetallic alloy displays notable strength and plasticity at room temperature, along with stable plastic flow at high homologous temperatures.

In this study, regenerated cellulose fibers were successfully prepared from cellulose/NaOH/thiourea/urea aqueous solution through an efficient extrusion dissolution method. The microstructure of the regenerated cellulose fibers were analysed by using attenuated total reflection infrared (ATR-IR) spectroscopy and the corresponding two-dimensional (2D) correlation spectroscopy. The results showed that the fibers demonstrate a typical crystalline cellulose II and a relatively high crystallinity. Improved crystal structure and tensile strength were obtained in the regenerated cellulose fibers due to improved multi-roller drawing process. The total crystalline index (TCI) and tensile strength of the fibers at different spinning stages were determined in the range of 0.46-0.54 and 1.06-2.30 cN/dtex, respectively. The described cellulose regeneration pathway provided an environmentally friendly and simple method, which could have a significant influence on current cellulose regeneration industries.

Fast radio bursts (FRBs) are millisecond-duration radio transients of unknown physical origin observed at extragalactic distances 1 – 3 . It has long been speculated that magnetars are the engine powering repeating bursts from FRB sources 4 – 13 , but no convincing evidence has been collected so far 14 . Recently, the Galactic magnetar SRG 1935+2154 entered an active phase by emitting intense soft γ-ray bursts 15 . One FRB-like event with two peaks (FRB 200428) and a luminosity slightly lower than the faintest extragalactic FRBs was detected from the source, in association with a soft γ-ray/hard-X-ray flare 18 – 21 . Here we report an eight-hour targeted radio observational campaign comprising four sessions and assisted by multi-wavelength (optical and hard-X-ray) data. During the third session, 29 soft-γ-ray repeater (SGR) bursts were detected in γ-ray energies. Throughout the observing period, we detected no single dispersed pulsed emission coincident with the arrivals of SGR bursts, but unfortunately we were not observing when the FRB was detected. The non-detection places a fluence upper limit that is eight orders of magnitude lower than the fluence of FRB 200428. Our results suggest that FRB–SGR burst associations are rare. FRBs may be highly relativistic and geometrically beamed, or FRB-like events associated with SGR bursts may have narrow spectra and characteristic frequencies outside the observed band. It is also possible that the physical conditions required to achieve coherent radiation in SGR bursts are difficult to satisfy, and that only under extreme conditions could an FRB be associated with an SGR burst. An 8-hour radio observational campaign of the Galactic magnetar SGR 1935+2154, assisted by multi-wavelength data, indicates that associations between fast radio bursts and soft γ-ray bursts are rare.

The CXCL12/CXCR4 axis has been posited widely to have significant roles in many primary tumors and metastases. It is known that CXCR7 can also be engaged by CXCL12, but the exact function of CXCR7 is controversial. This prompted us to investigate the expression, specific function and signal transduction of CXCR7 in hepatocellular carcinoma (HCC). In this study, CXCR7 and CXCR4 were differentially expressed in nine cell lines of HCC, and that elevated expression of both CXCR7 and CXCL4 were correlated with highly metastatic ability of HCC cells. Moreover, CXCR7 expression was significantly upregulated in metastatic HCC samples compared with the non-metastatic ones by staining of high-density tissue microarrays constructed from a cohort of 48 human HCC specimens. CXCR7 overexpression enhanced cell growth and invasiveness in vitro , and tumorigenicity and lung metastasis in vivo . By contrast, CXCR7 stable knockdown markedly reduced these malignant behaviors. In addition, it was observed that alterations in CXCR7 expression were positively correlated with the phosphorylation levels of mitogen-activated protein kinase (MAPK) pathway proteins. Targeting extracellular regulated kinase pathway by using U0126 inhibitor or using CCX771, a selective CXCR7 antagonist, drastically reduced CXCR7-mediated cell proliferation. Importantly, by using human biotin-based antibody arrays, several differentially expressed proteins were identified in CXCR7-overexpression and depletion groups. Comparative analysis indicated that upstream regulators including TP53 and IL-6 were involved in CXCR7 signal transduction. CXCR7 expression was further proved to regulate expression of vascular endothelial growth factor A and galectin-3, which may contribute to tumor angiogenesis and invasiveness. Consequently, elevated expression of CXCR7 contributes to HCC growth and invasiveness via activation of MAPK and angiogenesis signaling pathways. Targeting CXCR7 may prevent metastasis and provide a potential therapeutic strategy for HCC.

This study presents the design and integration of dual power wheels for a novel powered wheelchair driven by rim motors. Each power wheel is composed of a power train of a rim motor, drive, hybrid electromagnetic brake and battery bank. The installation of dual power wheels turns a manual foldable wheelchair into a powered wheelchair. The multifunctional optimisation design of two critical components, the rim motor and hybrid electromagnetic brake, is first introduced. A driving strategy is then proposed for the wheelchair with a stable soft-starting control, dual-wheel differential speed control, three-phase short-circuit brake control and magnetic particle brake control. The experimental results show that the novel powered wheelchair has better power economy than most commercial products in terms of driving range.

The underlying mechanisms associated with welding-induced buckling distortions are investigated using finite element procedures. Unlike stable type of welding-induced distortions which can be adequately captured by performing a thermo-plasticity simulation of actual welding procedures, local buckling distortions in welded structures are of an unstable type, which requires the use of appropriate buckling analysis procedures incorporating welding-induced residual stress state. With the underlying mechanisms in buckling distortions being established, two effective mitigation techniques were presented. One is trailing heat sink and the other is in-process synchronized rolling techniques. Detailed finite element simulations were performed to demonstrate how some of the important process parameters can be established in effectively reducing or eliminating the buckling distortions. The proposed techniques were also validated by laboratory welding trials. The underlying principles and potential applications of the distortion mitigation techniques are also discussed in light of the detailed finite element simulation results.

This research is mainly to explore functional improvement by adding various kinds of metallic ions in the ozonation of 2-chlorophenol solution. During the experiment, various kinds of metallic ions (Pb+, Cu2+, Zn2+, Fe2+, Ti2+, and Mn2+) were added; it was found that the reaction rate increased in all cases. The best result was obtained by using manganese ions, followed by iron and titanium ions. At pH = 3 and 1 ppm Mn2+ concentration, the reaction rate was increased by three times. TOC removal rate was also increased from 12.6% to 38% at 60 min reaction time. Ozone self-decomposition with various kinds of metallic ions alone was tested. It was found the ozone self-decomposition coefficient is highly dependent on the reaction rate constant for ozonation of 2-chlorophenol. The improvement of reaction was relevant to the mechanism of reaction between ozone and metallic ions. Furthermore, the effect of adding manganese ions was studied. With the initial manganese concentration at 0-2 ppm, after gas exposure for 20 min the removal rate can be increased from 38% to 93%. TOC removal rate was increased from 11% to 38%. The reaction rate was improved more greatly at the initial pH = 3.

Composite polymer electrolytes (CPEs) based on polyethylene oxide (PEO) offer manufacturing feasibility and outstanding mechanical flexibility. However, the low ionic conductivity of the CPEs at room temperature, as well as the poor mechanical properties, have hindered their commercialization. In this work, Solid-state electrolytes based on polyethylene oxide (PEO) with and without fumed SiO 2 (FS) nanoparticles are prepared by electrostatic spinning process. The as-spun PEO hybrid nanofiber electrolyte with 6.85 wt% FS has a relatively high lithium ion conductivity and electrochemical stability, which is 4.8 × 10 -4 S/cm and up to 5.2 V vs. Li + /Li, respectively. Furthermore, it also shows a higher tensile strength (2.03 MPa) with % elongation at break (561.8). Due to the superior electrochemical and mechanical properties, it is promising as high-safety and all-solid-state polymer electrolyte for advanced Li-metal battery.

The authors aim to provide a novel design of rim motors for electric wheelchairs, using the conventional rim as the motor on each wheel. The rotor of the rim motor is a conventional hand rim plugged inside its tube with a series of magnets of alternate N and S poles. Two sectors of arc stator are designed facing the inner side of the rim. This configuration enables a larger force-arm that multiplies the force exerted along the rim to produce a larger torque than the conventional hub-in motor of smaller radius. An optimal design procedure for a rim motor would make electric powered wheelchairs foldable, light, fuel-efficient and easy to operate. Experimental results show that the prototype rim motor satisfies the required specifications in terms of speed, torque, torque density and torque ripples. This rim motor provides a promising option for actuators and is a revolutionary product for electric powered wheelchairs.