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1.
Journal of Alloys and Compounds ; 952, 2023.
Article in English | Web of Science | ID: covidwho-2327350

ABSTRACT

In this paper, we reported on the lattice distortion, surface morphologies, vacancy defects and electrochemical performance that had been observed in Na3V2(PO4)2F3 prepared at different annealing temperatures. X-ray diffraction indicated that all the samples were single phase materials with tetragonal structure and exhibited lattice distortion with the increase of annealing temperatures. A possible mechanism causing the strain-induced lattice distortion had been discussed. Moreover, scanning electron microscopy and positron annihilation techniques were used to study the grain size and vacancy defects as a function of annealing temperatures. The superior electrochemical performance of Na3V2(PO4)2F3 electrode was obtained at the annealing temperature of 350 degrees C with 167.73 F center dot g-1 specific capacitance and 85% capacitance retention. The better electrochemical performance was due to the synergistic effects of grain size and vacancy defect regulated by the annealing temperatures. These results could provide experimental basis for enhancing electrochemical performance of Na3V2(PO4)2F3 in sodium-ion battery area applications. (c) 2023 Elsevier B.V. All rights reserved.

2.
Plasma Sources Science & Technology ; 30(5):17, 2021.
Article in English | Web of Science | ID: covidwho-1272949

ABSTRACT

The COVID-19, viral influenza, tuberculosis, and other widespread infectious diseases evidence that pathogenic biological aerosols (PBAs) are a serious threat to public health. Different from traditional inactivation methods, such as ultraviolet (UV) light which are only safe to use when people are not present, and high-efficiency particulate filters (HEPA) which merely filter microbes without killing them, atmospheric pressure nonequilibrium plasma (APNP) has shown its tremendous potential in drastically diminishing the aerosol transmission route of the infectious agents through the abatement of PBAs. The key issues to develop high performance APNP based air purification system are critically reviewed. Systematic studies on the hazards of different PBAs and the spread of PBAs in indoor environments guide the development of APNP sources to control communicable diseases. The key six sampling and seven detection methods on PBAs are introduced to analyze the PBA abatement efficiency by APNP. Seven common APNP sources which can remove viruses and bacteria aerosols efficiently developed during the past 8 years are introduced. For the APNP sources with small plasma volume, the electric field and diffusion driven charging are the dominant mechanisms to charge PBAs, while the common methods of dusty plasma research can be adapted to atmospheric-pressure conditions to describe the charging effects of APNP sources with large plasma volume. Plentiful long- and short-lifetime reactive oxygen and nitrogen species (RONS) generated by APNP effectively contribute to inactivation of bacterial aerosols. Current studies suggest that viral aerosols are mainly inactivated by short-lifetime RONS including O-1(2), ONOO- and ONOOH. The study on the dissolution and reaction of gaseous RONS in microdroplets and accurate measurements on the evolution of charged PBAs are envisaged to be the focus of future research. Opportunities for multidisciplinary collaborative research to advance the development of next-generation high-performance plasma-based air purifiers are highlighted.

4.
Zhonghua Jie He He Hu Xi Za Zhi ; 43(4): 327-331, 2020 Apr 12.
Article in Chinese | MEDLINE | ID: covidwho-3067

ABSTRACT

Objective: To study the epidemiological characteristics of COVID-19 in Henan Province. Methods: An epidemiological study was conducted based on the latest epidemic information of 1 265 confirmed cases (including regional distribution, severe illness, and deaths) announced by Health Commission of Henan Province, as well as the details of 1 079 COVID-19 officially released by Health Commission of municipalities in Henan Province collected as of 24: 00 on February 19, 2020. Results: Among 1 079 patients diagnosed with COVID-19, there were 573 male (53.2%) and 505 female (46.8%), with the ratio of male to female of 1.14∶1; The majority of patients were 36-59 years old (553 cases, 51.3%), and the mean age was 46 (interquartile range is 24) years old; 515 cases (47.7%) had a history of living, traveling, doing business in Wuhan or a brief stopover at Wuhan train stop, and 382 (35.4%) had a history of close contact with confirmed patients; There were 72 severe cases (5.7%) in 1 265 patients, and the fatality rate was 1.5%. A high number of cases were reported in Xinyang (269 cases, 21.26%), Zhengzhou (156 cases, 12.33%), Nanyang (155 cases, 12.25%), Zhumadian (139 cases, 10.99%), followed by Shangqiu (91 cases, 7.19%), Zhoukou (76 cases, 6.01%). Among 605 patients, the symptoms were fever (553 cases, 91.4%), debilitation (44 cases, 7.3%), cough (110 cases, 18.2%), expectoration (19 cases, 3.1%), chills (6 cases, 1.0%), shiver (7 cases, 1.2%), running nose (21 cases, 3.5%), stuffy noses (8 cases, 1.3%), throat dryness and sore (24 cases, 4.0%), headache (21 cases, 3.5%), chest pain (6 cases, 1.0%), anhelation (18 cases, 3.0%), and gastrointestinal symptom (21 cases, 3.5%). The age of deaths ranged from 33 to 86 years old, with an average age of 72 (interquartile range of 17) years old; there be 7 males (63.6%) and 4 females (36.4%). Conclusion: The cases in Henan Province were mainly imported cases and had certain geographical location relevance; meanwhile, there was a family-focused incidence. The overall trend of new cases was wave-like decline, and the number of deaths was high among elderly men with underlying diseases.


Subject(s)
Coronavirus Infections/epidemiology , Pneumonia, Viral/epidemiology , Adult , Aged , Aged, 80 and over , Betacoronavirus , COVID-19 , China/epidemiology , Coronavirus Infections/mortality , Female , Humans , Incidence , Male , Middle Aged , Pandemics , Pneumonia, Viral/mortality , SARS-CoV-2 , Travel
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