The accurate detection and classification of power quality (PQ) disturbances in power systems is a key step to determine the causes of these events before any proper countermeasure could be taken. ...This paper presents a new algorithm for detection and classification of PQ disturbances based on the combination of double-resolution S-transform (DRST) and directed acyclic graph support vector machines (DAG-SVMs). The proposed method first employs DRST for an effective feature extraction from power signals. Then, the DAG-SVMs are used to predict the classes of PQ disturbances. The DRST not only has better time-frequency localization and stronger robustness but also reduces the computational complexity without losing the useful information of the original signal in comparison with the traditional S-transform. Through the combined use of DRST and DAG-SVMs, the algorithm can be easily implemented in embedded real-time applications. Finally, the implementation of the proposed algorithm in a digital signal processor + advanced reduced instruction set computing machine-based hardware test platform is introduced. The effectiveness of the proposed method is demonstrated by means of computer simulations and practical experiments with single and combined PQ disturbances.
Developing therapeutics against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) could be guided by the distribution of epitopes, not only on the receptor binding domain (RBD) of the ...Spike (S) protein but also across the full Spike (S) protein. We isolated and characterized monoclonal antibodies (mAbs) from 10 convalescent COVID-19 patients. Three mAbs showed neutralizing activities against authentic SARS-CoV-2. One mAb, named 4A8, exhibits high neutralization potency against both authentic and pseudotyped SARS-CoV-2 but does not bind the RBD. We defined the epitope of 4A8 as the N-terminal domain (NTD) of the S protein by determining with cryo-eletron microscopy its structure in complex with the S protein to an overall resolution of 3.1 angstroms and local resolution of 3.3 angstroms for the 4A8-NTD interface. This points to the NTD as a promising target for therapeutic mAbs against COVID-19.
Abstract
Transition metal oxides (TMOs) are promising electrochromic (EC) materials for applications such as smart windows and displays, yet the challenge still exists to achieve good flexibility, ...high coloration efficiency and fast response simultaneously. MXenes (e.g. Ti
3
C
2
T
x
) and their derived TMOs (e.g. 2D TiO
2
) are good candidates for high-performance and flexible EC devices because of their 2D nature and the possibility of assembling them into loosely networked structures. Here we demonstrate flexible, fast, and high-coloration-efficiency EC devices based on self-assembled 2D TiO
2
/Ti
3
C
2
T
x
heterostructures, with the Ti
3
C
2
T
x
layer as the transparent electrode, and the 2D TiO
2
layer as the EC layer. Benefiting from the well-balanced porosity and connectivity of these assembled nanometer-thick heterostructures, they present fast and efficient ion and electron transport, as well as superior mechanical and electrochemical stability. We further demonstrate large-area flexible devices which could potentially be integrated onto curved and flexible surfaces for future ubiquitous electronics.
The year 2021 marks the 30th anniversary of the dissolution of the Soviet Union and Russia's transition from a planned to a market economy. It is also the 25th anniversary of the announcement of a ...strategic partnership of cooperation between China and Russia and the 20th anniversary of the signing of the China-Russia Treaty of Good Neighborliness and Friendly Cooperation. Therefore, 2021 is especially important both in terms of the development of contemporary Russia and the evolution of China-Russia relations. As the transitional economy of a great power, the Russian economy has distinctive characteristics; analysis of its economic transition and development over the past thirty years since the collapse of the Soviet Union, and especially in the period since Putin took office, is of immediate significance for observing the development of the Russian economy. At present, the profound changes the world is undergoing and alterations in the external environment present increasing uncertainties and obstacles to China-Russia economic and trade cooperation. This paper introduces the present state of China-Russia economic and trade cooperation and analyzes the new challenges and opportunities for future bilateral cooperation.
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•Nitrate and phosphate were simultaneously removed in SIBF.•Nitrate was removed by chemical reduction and NDFO without external carbon source.•Nitrate was removed by heterotrophic ...denitrification with external carbon source.•Phosphate was removed by chemical precipitation with the formation of FePO4.•Iron-oxidizing bacteria-Gallionellaceae was enriched in SIBF.
Sponge iron is a potential material for nitrogen and phosphate removal. To explore the performances and mechanisms of nitrogen and phosphate removal by sponge iron, a sponge iron biofilter was established. The results showed that nitrate was completely removed at HRT of 48 h without external carbon source and at HRT of 3 h with C/N ratio of 5. Furthermore, it was easy to achieve partial denitrification at HRT of 1 h with C/N ratio of 3. The mechanisms of nitrate removal were chemical reduction and nitrate dependent ferrous oxidation without external carbon source and heterotrophic denitrification with external carbon source. XPS result indicated that phosphate was removed by the formation of ferric phosphate precipitation. High throughput sequencing showed that iron-oxidizing bacteria Gallionellaceae was highly enriched in biofilter, accounting for 17.83%, which indicated that it was feasible to achieve autotrophic nitrate removal by sponge iron biofilter.
This paper presents a Fiber Bragg Grating (FBG)-based distal force sensor with a high sensitivity and a relatively large measurement range to provide force feedback for laparoscopic surgery. The ...proposed sensor design mainly consists of a force-sensitive flexure, one tightly suspended optical fiber embedded with an FBG sensing element and a contact head. The proposed flexure has been miniaturized based on improvement and optimization of a parallel structure form and a serial cantilever beam-based structure to achieve an excellent axial linear force-deformation relationship and a large measurement range. The optical fiber adopts a two-point pasting method, and has been tightly stretched and glued along the flexure's central line to achieve improved sensitivity and avoid FBG chirping failure. Finite element method (FEM)-based simulation has been performed to investigate both static and dynamic performances of the proposed design. The simulation-enabled optimization has been implemented to achieve optimal structural parameters and enhanced sensitivity. The optimized design has been prototyped and calibrated to demonstrate an excellent linearity with a small linearity error of 0.14% and achieve a high resolution of 21mN within a measurement range of 0, 12N. The further optimized version with the removal of small deformation constraint can reach a higher resolution of 9.3 mN within an operating range of 0, 7N. Dynamic loading experiments have been conducted to validate the effectiveness of the proposed designs.
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•Nitrate and nitrite reduction activities varied with biofilm structure changes.•Nitrite accumulated in different degree at different biofilm formation phases.•Hydraulic conditions ...affected biofilm structure and nitrate/nitrite reduction rates.•Partial denitrification was achieved at higher filtration velocity of 3.86mh−1.•Thauera genus bacteria became dominant denitrifiers when nitrite accumulated.
Partial denitrification was one of most effective ways to provide nitrite for annamox; whereas very limited research has been done to achieve nitrite accumulation in biofilm system. In this study, partial denitrification was studied in a lab-scale denitrifying biofilter (DNBF). The results showed biofilm structure variations caused the differences between nitrate specific reduction rate (NaSRR) and nitrite specific reduction rate (NiSRR), which led to nitrite accumulation in different degree at different biofilm formation phases. Hydrodynamic conditions also significantly influenced biofilm structure, nitrate and nitrite reduction activities. At the filtration velocity of 3.86mh−1, not only biofilm structure, NaSRR and NiSRR kept relatively stable, but also 60% of nitrite accumulation and no nitrate in the effluent were achieved. Furthermore, Thauera genus bacteria, benefited for nitrite accumulation, became the dominant communities in high nitrite accumulation conditions. The partial denitrification combine with anammox in biofilter have the great potential applied in WWTPs.
A series of activated aluminum/carbon/bismuth composites were prepared and characterized using scanning electron microscope (SEM) and X-ray diffraction (XRD). Then, the performance of these activated ...aluminum composites with respect to hydrogen generation was explored. The experimental results show that the hydrogen yield and generation rate of the aluminum composite are improved by adding carbon and bismuth to aluminum. In particular, the Al-7.5%nanoBi-2.5%GNS composite milled for 4 h demonstrated the best hydrogen generation in terms of yield and rate. The maximum hydrogen generation rate of Al-7.5%nanoBi-2.5%GNS composite could reach 23.3 mL s−1 g−1 at 30 °C. Besides, the relationship between initial reaction temperature, milling time, and hydrogen generation of these composites was studied. Moreover, the hydrolysis products of these aluminum composites were investigated.
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•Activated aluminum/carbon/bismuth composites are prepared by ball milling.•GNS and nano-Bi can effectively promote the hydrolysis reaction of aluminum.•Al-7.5%nanoBi-2.5%GNS shows the best hydrolysis performance.•Effects of GNS, Bi content on the hydrolysis performance of aluminum are studied.
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