Abstract
We present the discovery and timing results of four pulsars discovered in a pilot survey at intermediate Galactic latitudes with the Five-hundred Aperture Spherical Telescope (FAST). Among ...these pulsars, two belong to the category of millisecond pulsars (MSPs) with spin periods of less than 20 ms. The other two fall under the classification of “mildly recycled” pulsars, with massive white dwarfs as companions. Remarkably, this small survey, covering an area of 4.7 deg
2
, led to the discovery of four recycled pulsars. Such success underscores the immense potential of future surveys at intermediate Galactic latitudes. In order to assess the potential yield of MSPs, we conducted population simulations and found that both FAST and Parkes new phased array feed surveys, focusing on intermediate Galactic latitudes, have the capacity to uncover several hundred new MSPs.
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•Core/shell NiCo2O4@α-Co(OH)2 nanowires were synthesized by a two-step route first.•The optimized electrode exhibits a high specific capacitance of 1298 F g−1 at 1 A g−1.•An ...asymmetric capacitor of NiCo2O4@Co(OH)2//AC has an energy density of 39.7 Wh kg−1.
The composites of NiCo2O4 with unique structures are extensively explored as promising electrodes. In this work, core-shell structured nanowires anchored on nickel foam are synthesized by the hydrothermal synthesis of NiCo2O4 as core and subsequent electrodeposition of α-Co(OH)2 as shell. The core-shell composites exhibit enhanced electrochemical performances ascribing to the synergistic reactions from both materials, showing higher specific capacitance than any single component. By changing the deposition time, the mass loading of α-Co(OH)2 can be easily controlled. The electrochemical performances of the hybrid electrodes are diverse with the mass loading of Co(OH)2. The optimized hybrid electrode with 3 mins electrodeposition exhibits the highest specific capacitance (1298 F g−1 at 1 A g−1) among all electrodes. The redox reaction is a main contributor to the total specific capacitance through electrochemical kinetics analysis. An asymmetric supercapacitor assembled by the optimized material as positive electrode and activated carbon as negative electrode can achieve a relatively high energy density of 39.7 Wh kg−1 at a power density of 387.5 W kg−1 (at 0.5 A g−1) in a voltage of 1.55 V.
Aims
A thermostable endo‐mannanase from the fungus Talaromyces cellulolyticus was identified to facilitate manno‐oligosaccharide preparation from Konjac (Amorphophallus konjac) flour.
Methods and ...Results
A putative endo‐1,4‐β‐mannanase from the T. cellulolyticus was obtained and efficiently expressed by improving its gene dosage in the genome of the host. After cultivation in a bench‐top bioreactor for about 120 h, the protein content and enzyme activity of mannanase increased to 3·4 g l−1 and 17 500 U ml−1 respectively. Enzymatic characterization showed that this enzyme has an optimal temperature of 80°C, optimal pH of 5·0. Under the optimized hydrolysis conditions of pH 5·0, 70°C, and an enzyme concentration of 200 U l−1 solution, this enzyme could efficiently hydrolyse 0·5% konjac flour into manno‐oligosaccharides (MOSs) with the degree of polymerization range from 3 to 7. The possible mechanism by which the enzyme produced MOSs was also discussed.
Conclusion
Talaromyces cellulolyticus endo‐mannanase is thermostable and has a broad pH range adaptability. Method of improving the dosage of mannanase gene in the genome could realized its high‐level impression. This enzyme could efficiently hydrolyse konjac flour into manno‐oligosaccharide products.
Significance and Impact of the Study
This study has enriched endo‐mannanase resources, facilitated its bulk production and provided a strong reference for its application in manno‐oligosaccharide preparation from the natural glucomannan of konjac flour.
In this paper, we investigate the artificial noise-aided jamming design for a transmitter equipped with large antenna array in Rician fading channels. We figure out that when the number of transmit ...antennas tends to infinity, whether the secrecy outage happens in a Rician channel depends on the geometric locations of eavesdroppers. In this light, we first define and analytically describe the secrecy outage region (SOR), indicating all possible locations of an eavesdropper that can cause secrecy outage. After that, the secrecy outage probability (SOP) is derived, and a jamming-beneficial range, i.e., the distance range of eavesdroppers which enables uniform jamming to reduce the SOP, is determined. Then, the optimal power allocation between messages and artificial noise is investigated for different scenarios. Furthermore, to use the jamming power more efficiently and further reduce the SOP, we propose directional jamming that generates jamming signals at selected beams (mapped to physical angles) only, and power allocation algorithms are proposed for the cases with and without the information of the suspicious area, i.e., possible locations of eavesdroppers. We further extend the discussions to multiuser and multi-cell scenarios. At last, numerical results validate our conclusions and show the effectiveness of our proposed jamming power allocation schemes.
There is a worldwide interest in studying SLC26A4 mutations that are responsible for enlarged vestibular aqueduct (EVA) in different ethnic background and populations. The spectrum of SLC26A4 ...mutations in Chinese population is yet to be fully characterized. In this study, all the 21 exons of SLC26A4 were screened in 107 Chinese patients with hearing loss associated with EVA or both EVA and Mondini dysplasia (MD), taken from six multiplex and 95 simplex families. The two types of control populations consisted of 84 normal‐hearing subjects and 46 sensorineural hearing loss subjects without inner ear malformations. Biallelic mutations were found in 12 patients from multiplex families and 84 patients (88.4%) from the simplex families. In addition, monoallelic variant was detected in nine patients in the remaining 11 simplex families. Overall, up to 97.9% patients were found having at least one possible pathogenic variant in SLC26A4, with most having biallelic variants consistent with recessive inheritance of this disorder. A total of 40 mutations including 25 novel mutations were identified in the Chinese patients but were not detected in all the controls except for one normal subject. For the Chinese mutation spectrum of SLC26A4 gene, IVS7‐2A>G mutation was the most common form accounting for 57.63% (102/177) of all the mutant alleles.
ABSTRACT In this paper we show that the most luminous supernova discovered very recently, ASASSN-15lh, could have been powered by a newborn ultra-strongly magnetized pulsar, which initially rotates ...near the Kepler limit. We find that if this pulsar is a neutron star, its rotational energy could be quickly lost as a result of gravitational-radiation-driven r-mode instability; if it is a strange quark star (SQS), however, this instability is highly suppressed due to a large bulk viscosity associated with the nonleptonic weak interaction among quarks and thus most of its rotational energy could be extracted to drive ASASSN-15lh. Therefore, we conclude that such an ultra-energetic supernova provides a possible signature for the birth of an SQS.
In the study, a new triple-helix polysaccharide with favorable stability was purified from C. cornucopioides. Its structural characterization, stability and solution behavior were investigated by the ...GC–MS, periodate oxidation-smith degradation, FT-IR, 1D and 2D NMR spectroscopy, methylation analysis, Scanning electron microscope, Congo-red, CD, TGA and DSC analysis. The results showed that Craterellus cornucopioide polysaccharide (CCP) possessed the molecular weight of 1.97 × 103 kDa, is mainly composed of mannose (48.73%), galactose (17.37%), glucose (15.97%) and xylose (17.93%), respectively. It was a heteroglycan with (1 → 3)‑linked‑β‑d‑Manp‑(1 → 6)‑linked α‑d‑Galp backbone distributed by (1 → 4)‑linked‑α‑d‑Xylp‑t‑α‑d‑Manp and t‑β‑d‑Glup units at O-6. The result of TGA and DSC assay indicated that CCP has a favorable thermal stability. MTT and Scanning electro microscopy (SEM) assay showed that CCP could significantly improve the proliferation activity and induce cells activation of RAW264.7 in a certain range of concentrations and period.
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•We found and investigated a novel polysaccharide from Craterellus cornucopioides.•The Conformation studies of this polysaccharide solution was studied.•The structure stability of this polysaccharide was studied.•The morphological changes of RAW264.7 cells under CCP activation was observed.
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•Four types of new refractory HEAs are designed.•These HEAs mainly consist of a simple BCC solid solution.•The formation mechanism of β-Ti is proposed.•Oxidation resistance is ...improved by adding Ti and Si, but reduced by adding V.
High-entropy alloys (HEAs) are defined as the alloys composed of at least five principal elements in equimolar or near equimolar ratios, which can facilitate the formation of simple solid solutions during solidification. Recent studies suggested that the refractory HEAs exhibited great promise for high temperature structural materials. However, their oxidation behavior had received little attention. In the present study, Cr, Al and Si elements were added to improve the oxidation resistance, four types of new refractory HEAs were designed and synthesized, including NbCrMoTiAl0.5 (H-Ti), NbCrMoVAl0.5 (H-V), NbCrMoTiVAl0.5 (H-TiV) and NbCrMoTiVAl0.5Si0.3 (H-TiVSi0.3). Their microstructures and oxidation behavior were studied. As expected, these refractory HEAs mainly consist of a simple body-centred cubic (BCC) refractory metal solid solution (RMss) due to the high mixing entropy effect. Solidification process and thermodynamic analysis were investigated to explain the formation mechanism of their microstructures. For all the refractory HEAs, the oxidation kinetics at 1300°C follows a linear behavior. The oxidation resistance of the HEAs is significantly improved with Ti and Si addition, but reduced with V addition.
Federated learning (FL) has been considered as a promising paradigm for enabling distributed training/learning in many machine-learning services without revealing users' local data. Driven by the ...growing interests in exploiting FL in wireless networks, this paper studies the Non-orthogonal Multiple Access (NOMA) assisted FL in which a group of end-devices (EDs) form a NOMA cluster to send their locally trained models to the cellular base station (BS) for model aggregation. In particular, we consider that the BS adopts wireless power transfer (WPT) to power the EDs (for their data transmission and local training) in each round of FL iteration, and formulate a joint optimization of the BS's WPT for different EDs, the EDs' NOMA-transmission for sending the local models to the BS, the BS's broadcasting of the aggregated model to all EDs, the processing-rates of the BS and EDs, as well as the training-accuracy of the FL, with the objective of minimizing the system-wise cost accounting for the total energy consumption as well as the FL convergence latency. In spite of the strict non-convexity of the joint optimization problem, we analytically characterize the BS's and all EDs' optimal processing-rates, based on which we propose a layered algorithm for finding the optimal solutions for the joint optimization problem via exploiting monotonic optimization. Numerical results validate that our algorithm can achieve the optimal solution as LINGO's global-solver (i.e., a commercial optimization package) while significantly reducing the computation-time. Moreover, the results also demonstrate that our NOMA assisted FL can reduce the system cost compared to the benchmark FL scheme with the fixed local training-accuracy by more than 70% and the conventional frequency division multiple access (FDMA) based FL by 78%.
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