The purpose of this study is to investigate how genres vary and figure out the factors that generate genre variation. The quantitative multi-dimensional analysis is used to examine genre variation of ...cross-border e-commerce English in South Asia. The texts in the observed corpus collected from four country websites of Daraz, a significant cross-border e-commerce platform, were tagged and analyzed using Multidimensional Analysis Tagger and SPSS statistical software. The results of linear regression analysis, independent sample t-test and Analysis of Variance show salient differences between the observed corpus and reference corpus. The research also indicates that four sub-corpora from country Websites are brought into line with each other. They show salient differences (p<0.05) with the general corpus in two dimensions of linguistic variation. The findings indicate that variables that lead to the cross-border e-commerce English genre variation might be attributable to cultural backgrounds, regional market sizes, and fundamental internet facilities. In conclusion, these findings lend significant empirical support to systemic functional theories and suggest further research in the application of a multi-dimensional analysis approach in the cross-border e-commerce English genre.
Studies are carried out on the equilibrium structural, mechanical properties, and melting points of NbSi2 with four ground‐state crystal structures (C40, C11b, C54, and C49) using first‐principles ...approach. By means of the calculated formation enthalpies and phonon dispersion, it is found that these NbSi2 phases are thermodynamically and dynamically stable. C54‐NbSi2 is uncovered to possess the lowest energy and formation enthalpy, implying that it is expected to be the most favorite structure for NbSi2. The results of the calculated elastic constants reveal that four NbSi2 phases are mechanically stable. We further find that the mechanical properties of C54‐NbSi2 are superior to those of the other NbSi2 phases. The melting points of these NbSi2 phases are calculated to examine their thermal stability. The elastic anisotropy is calculated and discussed using three patterns. The results prove that C54‐ and C40‐NbSi2 have good elastic isotropy, as confirmed by the given three‐dimensional plots of elastic moduli. Analyzing the difference charge density and Mulliken overlap population provides the explanation about the relationship between bonding characteristics and mechanical properties.
A novel NbSi2 with C54 structure is predicted. This structure not only shows more thermodynamically stable, but also exhibits high elastic stiffness.
Abstract
Electromagnetic induction is the basis of most electrical and power equipment. In order to improve the overall performance of electromagnetic induction devices, it is necessary to analyze ...the distribution of electric and magnetic fields around and inside the devices, and guide the structural adjustment and material selection of devices. However, due to the integral and differential operations involved, complex electrical and magnetic field problems are often unable to be analyzed by analytical methods. With the improvement of numerical analysis theory and computer performance, the use of finite element analysis is expected to solve the complex electromagnetic field problems in practical applications. Using finite element analysis, the electromagnetic field distribution characteristics and influencing factors of electromagnetic induction devices of household induction cooker are studied, the corresponding mathematical model is established, the influence of electromagnetic parameters of each part of the induction heating system on heating energy efficiency is studied, and the optimization design is carried out according to different application requirements, so as to provide a basis for further improving the performance of devices.
Abstract
With the continuous advancement of information technology and the rapid development of mobile communication technology, from smart home to automatic driving of cars, and then to the ...application and development of virtual reality, communication technology has evolved from the earliest communication between people to communication between things. The frequency band supported by smart phones and various small mobile terminals is increasing, and their communication frequency is also gradually increasing, which brings some challenges to the traditional RF front-end devices. The traditional RF filter can not meet the current market demand because of its own performance and size constraints. As the best option to integrate with RF circuit or microwave circuit, bulk acoustic wave filter has great development and application prospects in modern RF communication system. This paper will focus on the solid-state assembled resonators based on one-dimensional and two-dimensional phononic crystals, analyze the influence and change law of the performance of bulk acoustic wave devices based on two-dimensional phononic crystals, then explore the main loss mechanism existing in solid-state assembled devices, and propose improvement schemes, which lays a foundation for the application of solid-state assembled resonators in today’s RF front-end.
Abstract
Quantum key distribution provides a provably secure way for private key distribution, which enables the practical implementation of information retrieval that preserves both the user privacy ...and database security.
Hydrogen evolution reaction (HER) is a key step for electrochemical energy conversion and storage. Developing well defined nanostructures as noble‐metal‐free electrocatalysts for HER is promising for ...the application of hydrogen technology. Herein, it is reported that 3D porous hierarchical CoNiP/CoxP multi‐phase heterostructure on Ni foam via an electrodeposition method followed by phosphorization exhibits ultra‐highly catalytic activity for HER. The optimized CoNiP/CoxP multi‐phase heterostructure achieves an excellent HER performance with an ultralow overpotential of 36 mV at 10 mA cm−2, superior to commercial Pt/C. Importantly, the multi‐phase heterostructure shows exceptional stability as confirmed by the long‐term potential cycles (30,000 cycles) and extended electrocatalysis (up to 500 h) in alkaline solution and natural seawater. Experimental characterizations and DFT calculations demonstrate that the strong electronic interaction at the heterointerface of CoNiP/CoP is achieved via the electron transfer from CoNiP to the heterointerface, which directly promotes the dissociation of water at heterointerface and desorption of hydrogen on CoNiP. These findings may provide deep understanding on the HER mechanism of heterostructure electrocatalysts and guidance on the design of earth‐abundant, cost‐effective electrocatalysts with superior HER activity for practical applications.
The CoNiP/CoxP multi‐phase heterostructure with 3D porous hierarchical morphology optimizes the electronic structure, thereby reducing the energy barrier for water dissociation, increasing the adsorption energy of H2O and OH−, and achieving near‐zero Gibbs free energy of hydrogen adsorption. A novel HER mechanism on CoNiP/CoxP multi‐phase heterostructure is proposed to be the water dissociation on heterointerface and H2 production on CoNiP.
An improved method to synthesize 1‐glycosyl thioacetates was developed, where per‐O‐acetylated glycoses were allowed to directly react with potassium thioacetate (KSAc) in the presence of BF3 ⋅ Et2O ...in ethyl acetate under mild conditions. This method not only overcomes the disadvantage of the traditional one‐step method, which is that the odorous and toxic thioacetic acid has to be used, but also overcomes the disadvantage of the traditional two‐step method, which is that the unstable intermediate, glycosyl halide, has to be synthesized from the per‐O‐acetylated glycose in advance. Based on this, the per‐O‐acetylated glucosyl disulfide and the per‐O‐acetylated glucosyl 1‐thiol were efficiently synthesized in high yields (91 % and 90 % respectively) starting from per‐O‐acetylated glycoses in two‐step without the need to isolate intermediate products. Through metal‐catalyzed cross‐coupling of per‐O‐acetylated glucosyl 1‐thiol with aryl‐iodide under very mild conditions, two thioglucoside gliflozin analogues were efficiently synthesized in high yields for the first time. These two thioglucoside gliflozin analogues were further confirmed to be stable to hydrolysis of β‐glucosidase.
We reported relative green synthesis of 1‐thioglycosides by straightforward reaction of per‐O‐acetylated glycoses with KSAc in EtOAc. Furthermore, the highly efficient method to synthesize per‐O‐acetylated glycosyl disulfide and glycosyl 1‐thiol were developed. Based on this, the synthesis of auranofin was improved and two thioglucoside gliflozin analogues (possible SGLT inhibitors) were efficiently synthesized in high yields.
Abstract
Gaining knowledge and actionable insights from complex, high-dimensional and heterogeneous biomedical data remains a key challenge in transforming health care. Various types of data have ...been emerging in modern biomedical research, including electronic health records, imaging, -omics, sensor data and text, which are complex, heterogeneous, poorly annotated and generally unstructured. Traditional data mining and statistical learning approaches typically need to first perform feature engineering to obtain effective and more robust features from those data, and then build prediction or clustering models on top of them. There are lots of challenges on both steps in a scenario of complicated data and lacking of sufficient domain knowledge. The latest advances in deep learning technologies provide new effective paradigms to obtain end-to-end learning models from complex data. In this article, we review the recent literature on applying deep learning technologies to advance the health care domain. Based on the analyzed work, we suggest that deep learning approaches could be the vehicle for translating big biomedical data into improved human health. However, we also note limitations and needs for improved methods development and applications, especially in terms of ease-of-understanding for domain experts and citizen scientists. We discuss such challenges and suggest developing holistic and meaningful interpretable architectures to bridge deep learning models and human interpretability.
Particulate matter (PM) pollutants, including nanoscale particles (NPs), have been considered serious threats to public health. In this work, a self-powered air filter that can be used in ...high-efficiency removal of PM, including NPs, is presented. An ionic liquid-polymer (ILP) composite is irregularly distributed onto a sponge network to form an ILP@MF filter. Enabled by its unique electrochemical properties, the ILP@MF filter can remove PM
and PM
with high efficiencies of 99.59% and 99.75%, respectively, after applying a low voltage. More importantly, the charged ILP@MF filter realizes a superior removal for NPs with an efficiency of 93.77%. A micro-button lithium cell or silicon-based solar panel is employed as a power supply platform to fabricate a portable and self-powered face mask, which exhibits excellent efficacy in particulate removal compared to commercial masks. This work shows a great promise for high-performance purification devices and facile mask production to remove particulate pollutants.
The contents of ten heavy metals (Cr, Hg, As, Pb, Ni, Cd, Ti, Cu, Zn and V) in 413 topsoil samples from Puning City, Guangdong Province, China were investigated. Obvious enrichment of Hg, As, Pb, Cd ...and Zn were presented, and the contents of Hg and As in 5.8% and 3.4% samples respectively were higher than the guideline values recommended by the Chinese Environmental Quality Standard for Soils. Chromium and V were presented no enrichment and no pollution. According to one-way analysis of variance, the mean contents of Hg, Pb, Cu and Zn in land for construction were significantly higher than farmland and natural vegetation, but the land use had no obvious effect on other heavy metals. Furthermore, the potential sources of ten heavy metals were identified and apportioned in combination with geostatistics, correlation analysis and positive matrix factorization model. The results were following as: a) Pb, Zn and Cu mainly origin from vehicle emission and atmosphere deposition, and the hotspots approximately distributed in the areas of intensive traffic and near main roads; b) Hg and Cd were derived to industrial activities related to pharmaceutical industries, the textile and dyeing industries and e-waste recycling industries, and high-value areas were mainly concentrated in the northeast of the urban area where the industrial parks have been distributed; c) Soil parent material (Jurassic shale) was the main source of Cr, Ni, V and Ti; d) As mainly came from agricultural inputs such as pesticides or herbicides, livestock and fertilizers. Meanwhile, the contributions of four sources were 33.08%, 24.04%, 27.11% and 15.77% of the total contribution, respectively.
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•Obvious enrichment of Hg, Cd, Pb and Zn were found in Puning soils.•Four sources of soil heavy metals were apportioned by geostatistics and PMF.•Vehicle emission and industrial activities were the main anthropogenic source.
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