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Fast radio bursts (FRBs) are millisecond-duration radio transients 1 , 2 of unknown origin. Two possible mechanisms that could generate extremely coherent emission from FRBs invoke neutron star magnetospheres 3 – 5 or relativistic shocks far from the central energy source 6 – 8 . Detailed polarization observations may help us to understand the emission mechanism. However, the available FRB polarization data have been perplexing, because they show a host of polarimetric properties, including either a constant polarization angle during each burst for some repeaters 9 , 10 or variable polarization angles in some other apparently one-off events 11 , 12 . Here we report observations of 15 bursts from FRB 180301 and find various polarization angle swings in seven of them. The diversity of the polarization angle features of these bursts is consistent with a magnetospheric origin of the radio emission, and disfavours the radiation models invoking relativistic shocks. Polarization observations of the fast radio burst FRB 180301 with the FAST radio telescope show diverse polarization angle swings, consistent with a magnetospheric origin of the emission.

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.

Engineering analysis of slope stability includes three separate but interrelated phases: (a) experimental strength measurements, (b) determination of a strength envelope that best fits the experimental results, and (c) formal limiting equilibrium analysis using the resulting strength envelopes. Studying the interrelations between these phases leads to an integrated approach to slope stability analysis. The present work uses a single experimental database that is fitted with both linear (Mohr–Coulomb) and nonlinear failure envelopes and investigates the effect of different forms of the failure criterion on slope stability computations for both 2D and 3D problems. It has been indicated that calculated minimum safety factors could be significantly overestimated by the linear approximation of a nonlinear strength envelope. The effect of neglecting strength envelope nonlinearity is more pronounced under 3D conditions than in a 2D simplification. As a result, the use of nonlinear failure criterions in slope stability analyses is recommended to account for the stress-dependent nature of the shear strength of soils.Key words: nonlinear strength envelope, Mohr–Coulomb failure criterion, limit equilibrium, critical slip surface, minimum factor of safety, three-dimensional stability analysis.

Additive manufacturing is becoming increasingly popular because of its unique advantages, especially fused deposition modelling (FDM) which has been widely used due to its simplicity and comparatively low price. However, in current FDM processes, it is difficult to fabricate parts with highly accurate dimensions. One of the reasons is due to the slicing process of 3D models. Current slicing software divides the parts into layers and then lines (paths) based on a fixed value. However, in a real printing process, the printed line width will change when the process parameters are set in different values. The various printed widths may result in inaccuracy of printed dimensions of parts if using a fixed value for slicing. In this paper, a mathematical model is proposed to predict the printed line width in different layer heights. Based on this model, a method is proposed for calculating the optimal width value for slicing 3D parts. In the future, the proposed mathematical model can be integrated into slicing software to slice 3D models for precision additive manufacturing.

In the fields of new energy vehicles, energy storage systems, and electronic devices, the battery management system is one of the key technologies to ensure the performance and safety of the battery pack, and the estimation of the battery state of charge (SoC) is an important part of it. To solve the problem of the difficulty in accurately estimating the SoC of current lithium-ion batteries, this paper selects the dual-polarization circuit model to represent the external electrical characteristics of the battery, and identifies the model parameters. Then, under the New European Driving Cycle (NEDC) and Federal Urban Driving Schedule (FUDS) operating condition data, the Extended Kalman Filter (EKF) is used to estimate the SoC of the lithium-ion battery. The simulation results show that this SoC estimation method has the characteristics of high accuracy, fast convergence speed, and good robustness, which verifies the accuracy and effectiveness of the lithium-ion battery bipolar equivalent circuit model combined with the EKF algorithm to estimate the SoC of the lithium-ion battery.

Adenylyl cyclase 2 (ADCY2), a class B member of adenylyl cyclases, is important in accelerating phosphor-acidification as well as glycogen synthesis and breakdown. Given its distinct role in flesh tenderization after butchering, we cloned and sequenced the ADCY2 gene from Yanbian cattle and assessed its expression in bovine tissues. A 2947 bp nucleotide sequence representing the full-length cDNA of bovine ADCY2 gene was obtained by 5′ and 3′ remote analysis computations for gene expression. Analyses of the putative protein sequence showed that ADCY2 had high homology among species, except with the non-mammal Oreochromis niloticus. Gene structural domain analyses in humans and rats indicated that the ADCY2 protein had no flaw; only the transmembrane domain was reduced and the CYCc structure domain was shortened. Assessment of ADCY2 expression in bovine tissues by real-time PCR showed that the highest expression was in the testes, followed by the longissimus dorsi, tensor fasciae latae, and latissimus dorsi. These data will serve as a foundation for further insight into the cattle ADCY2 gene.

Recently, amorphous Hf-B-Si-C-N coatings found to demonstrate superior high-temperature oxidation resistance. The microstructure evolution of two coatings, Hf 7 B 23 Si 22 C 6 N 40 and Hf 6 B 21 Si 19 C 4 N 47 , annealed to 1500 °C in air is investigated to understand their high oxidation resistance. The annealed coatings develop a two-layered structure comprising of the original as-deposited film followed by an oxidized layer. In both films, the oxidized layer possesses the same microstructure with HfO 2 nanoparticles dispersed in an amorphous SiO x -based matrix. The bottom layer in the Hf 6 B 21 Si 19 C 4 N 47 coating remains amorphous after annealing while Hf 7 B 23 Si 22 C 6 N 40 recrystallized partially showing a nanocrystalline structure of HfB 2 and HfN nanoparticles separated by h-Si 3 N 4 and h-BN boundaries. The HfB 2 and HfN nanostructures form a sandwich structure with a HfB 2 strip being atomically coherent to HfN skins via (111)-Hf monolayers. In spite of the different bottom layer structure, the oxidized/bottom layer interface of both films was found to exhibit a similar microstructure with a fine distribution of HfO 2 nanoparticles surrounded by SiO 2 quartz boundaries. The high-temperature oxidation resistance of both films is attributed to the particular evolving microstructure consisting of HfO 2 nanoparticles within a dense SiO x -based matrix and quartz SiO 2 in front of the oxidized/bottom layer interface acting as a barrier for oxygen and thermal diffusion.

A natural plasticizer cardanol derivatives glycidyl ether (CGE) was synthesized and employed as a plasticizer for the poly(vinyl chloride). The effect of CGE on thermal degradation of PVC films and its plasticizing mechanism were firstly reported. The molecular structure of CGE was characterized with Fourier transform infrared spectroscopy (FTIR). Thermal properties, degradation properties and compatibility of the PVC films were investigated by Differential scanning calorimeter analysis (DSC), Thermogravimetric analysis (TGA) and FTIR, respectively. Compared with the commercial plasticizers dioctylphthalate (DOP), CGE can endow PVC film with a decrease of 4.31 °C in glass transition temperature (Tg), an increase of 24.01 °C and 25.53 °C in 10% weight loss (T10) and 50% weight loss (T50) respectively, and a higher activetion energy of thermal degradation (Ea).

Issue Title: International Conference on Bioenergy Technologies and Joint Symposium with AIChE Forest Products Division, Nanjing, China, October 2012