17 research outputs found
Modeling and simulation in supersonic three-temperature carbon dioxide turbulent channel flow
This paper pioneers the direct numerical simulation (DNS) and physical
analysis in supersonic three-temperature carbon dioxide (CO2) turbulent channel
flow. CO2 is a linear and symmetric triatomic molecular, with the thermal
non-equilibrium three-temperature effects arising from the interactions among
translational, rotational and vibrational modes under room temperature. Thus,
the rotational and vibrational modes of CO2 are addressed. Thermal
non-equilibrium effect of CO2 has been modeled in an extended three-temperature
BGK-type model, with the calibrated translational, rotational and vibrational
relaxation time. To solve the extended BGK-type equation accurately and
robustly, non-equilibrium high-accuracy gas-kinetic scheme is proposed within
the well-established two-stage fourth-order framework. Compared with the
one-temperature supersonic turbulent channel flow, supersonic three-temperature
CO2 turbulence enlarges the ensemble heat transfer of the wall by approximate
20%, and slightly decreases the ensemble frictional force. The ensemble density
and temperature fields are greatly affected, and there is little change in Van
Driest transformation of streamwise velocity. The thermal non-equilibrium
three-temperature effects of CO2 also suppress the peak of normalized
root-mean-square of density and temperature, normalized turbulent intensities
and Reynolds stress. The vibrational modes of CO2 behave quite differently with
rotational and translational modes. Compared with the vibrational temperature
fields, the rotational temperature fields have the higher similarity with
translational temperature fields, especially in temperature amplitude. Current
thermal non-equilibrium models, high-accuracy DNS and physical analysis in
supersonic CO2 turbulent flow can act as the benchmark for the long-term
applicability of compressible CO2 turbulence.Comment: Carbon dioxide flow, Vibrational modes, Three-temperature effects,
Supersonic turbulent channel flow
Development of a specific monoclonal antibody-based ELISA to measure the artemether content of antimalarial drugs.
Artemether is one of the artemisinin derivatives that are active ingredients in antimalarial drugs. Counterfeit and substandard antimalarial drugs have become a serious problem, which demands reliable analytical tools and implementation of strict regulation of drug quality. Structural similarity among artemisinin analogs is a challenge to develop immunoassays that are specific to artemisinin derivatives. To produce specific antibodies to artemether, we used microbial fermentation of artemether to obtain 9-hydroxyartemether, which was subsequently used to prepare a 9-O-succinylartemether hapten for conjugation with ovalbumin as the immunogen. A monoclonal antibody (mAb), designated as 2G12E1, was produced with high specificity to artemether. 2G12E1 showed low cross reactivities to dihydroartemisinin, artemisinin, artesunate and other major antimalarial drugs. An indirect competitive enzyme linked immunosorbent assay (icELISA) developed showed a concentration causing 50% of inhibition for artemether as 3.7 ng mLâ»Âč and a working range of 0.7-19 ng mLâ»Âč. The icELISA was applied for determination of artemether content in different commercial drugs and the results were comparable to those determined by high-performance liquid chromatography analysis. In comparison with reported broad cross activity of anti-artemisinin mAbs, the most notable advantage of the 2G12E1-based ELISA is its high specificity to artemether only
Pattern of COVID-19 in Sichuan province, China: A descriptive epidemiological analysis.
This study described the epidemiology of 487 confirmed coronavirus disease 2019 (COVID-19) cases in Sichuan province of China, and aimed to provide epidemiological evidence to support public health decision making. Epidemiological information of 487 COVID-19 cases were collected from the official websites of 21 districts (including 18 cities, 3 autonomous prefecture) health commissions within Sichuan between 21st of January 2020 to 17th of April 2020. We focus on the single-day diagnosis, demographics (gender and age), regional distribution, incubation period and symptoms. The number of single-day confirmed COVID-19 cases reach a peak on January 29 (33 cases), and then decreased. Chengdu (121 cases), Dazhou (39 cases) Nanchong (37 cases) and Ganzi Tibetan Autonomous Prefecture (78 cases) contributed 275 cases (56.5% of the total cases) of Sichuan province. The median age of patients was 44.0 years old and 52.6% were male. The history of living in or visiting Hubei, close contact, imported and unknown were 170 cases (34.9%), 136 cases (27.9%), 21 cases (4.3%) and 160 cases (32.9%) respectively. The interval from the onset of initial symptoms to laboratory diagnosis was 4.0 days in local cases, while that of imported cases was 4.5 days. The most common symptoms of illness onset were fever (71.9%) and cough (35.9%). The growth rate of COVID-19 in Sichuan has significantly decreased. New infected cases have shifted from the living in or visiting Wuhan and close contact to imported. It is necessary to closely monitor the physical condition of imported cases
Deciphering Electrolyte Dominated Na+ Storage Mechanisms in Hard Carbon Anodes for SodiumâIon Batteries
Abstract Although hard carbon (HC) demonstrates superior initial Coulombic efficiency, cycling durability, and rate capability in etherâbased electrolytes compared to esterâbased electrolytes for sodiumâion batteries (SIBs), the underlying mechanisms responsible for these disparities remain largely unexplored. Herein, ex situ electron paramagnetic resonance (EPR) spectra and in situ Raman spectroscopy are combined to investigate the Na storage mechanism of HC under different electrolytes. Through deconvolving the EPR signals of Na in HC, quasiâmetallicâNa is successfully differentiated from adsorbedâNa. By monitoring the evolution of different Na species during the charging/discharging process, it is found that the initial adsorbedâNa in HC with etherâbased electrolytes can be effectively transformed into intercalatedâNa in the plateau region. However, this transformation is obstructed in esterâbased electrolytes, leading to the predominant storage of Na in HC as adsorbedâNa and poreâfilledâNa. Furthermore, the intercalatedâNa in HC within the etherâbased electrolytes contributes to the formation of a uniform, dense, and stable solidâelectrolyte interphase (SEI) film and eventually enhances the electrochemical performance of HC. This work successfully deciphers the electrolyteâdominated Na+ storage mechanisms in HC and provides fundamental insights into the industrialization of HC in SIBs