Emerging mobile technologies can be considered a new form of social and cultural artefact that mediates people's language learning. This multi-case study investigates how mobile technologies mediate ...a group of Hong Kong university students' L2 learning, which serves as a lens with which to capture the personalised, unique, contextual and ubiquitous nature of mobile language learning. The results suggest that Hong Kong university students make use of varied e-resources and tools for learning their L2; they also tend to combine L2 learning with subject learning, communication, entertainment and personal interests, and reveal distinctive features and attributes that form their personalised learning approaches. Based on these, a new socio-cultural framework is constructed to capture the key components involved in mobile technologies-mediated L2 learning and to describe the dynamism and interaction among the components, involving L2 agency, personalisation, tools, knowledge, communications and entertainment. In addition, L2 agency plays an important role in determining how learners employ mobile technologies in mediating and personalising their language learning. Factors that influence personalised mobile language learning are also unveiled. Finally, a number of implications are derived from the research findings to inform further research or practice with regard to mobile language learning.
The surge of patients in the pandemic of COVID‐19 caused by the novel coronavirus SARS‐CoV‐2 may overwhelm the medical systems of many countries. Mask‐wearing and handwashing can slow the spread of ...the virus, but currently, masks are in shortage in many countries, and timely handwashing is often impossible. In this study, the efficacy of three types of masks and instant hand wiping was evaluated using the avian influenza virus to mock the coronavirus. Virus quantification was performed using real‐time reverse transcription‐polymerase chain reaction. Previous studies on mask‐wearing were reviewed. The results showed that instant hand wiping using a wet towel soaked in water containing 1.00% soap powder, 0.05% active chlorine, or 0.25% active chlorine from sodium hypochlorite removed 98.36%, 96.62%, and 99.98% of the virus from hands, respectively. N95 masks, medical masks, and homemade masks made of four‐layer kitchen paper and one‐layer cloth could block 99.98%, 97.14%, and 95.15% of the virus in aerosols. Medical mask‐wearing which was supported by many studies was opposed by other studies possibly due to erroneous judgment. With these data, we propose the approach of mask‐wearing plus instant hand hygiene (MIH) to slow the exponential spread of the virus. This MIH approach has been supported by the experiences of seven countries in fighting against COVID‐19. Collectively, a simple approach to slow the exponential spread of SARS‐CoV‐2 was proposed with the support of experiments, literature review, and control experiences.
J/ψ polarization in the CGC+NRQCD approach Ma, Yan-Qing; Stebel, Tomasz; Venugopalan, Raju
The journal of high energy physics,
12/2018, Letnik:
2018, Številka:
12
Journal Article
Recenzirano
Odprti dostop
A
bstract
We compute the
J/ψ
polarization observables
λ
θ
,
λ
ϕ
,
λ
θϕ
in a Color Glass Condensate (CGC) + nonrelativistic QCQ (NRQCD) formalism that includes contributions from both color singlet ...and color octet intermediate states. Our results are compared to low
p
T
data on
J/ψ
polarization from the LHCb and ALICE experiments on proton-proton collisions at center-of-mass energies of
s
=
7
TeV and 8 TeV. Our CGC+NRQCD computation provides a better description of data for
p
T
≤ 15 GeV relative to extant next-to-leading (NLO) calculations within the collinear factorization framework. These results suggest that higher order computations in the CGC+NRQCD framework have the potential to greatly improve the accuracy of extracted values of the NRQCD universal long distance matrix elements.
We employ a small x color glass condensate (CGC)+ nonrelativistic QCD (NRQCD) formalism to compute J/ψ production at low p(⊥) in proton-proton collisions at collider energies. Very good agreement is ...obtained for total cross sections, rapidity distributions, and low momentum p(⊥) distributions. Similar agreement is obtained for ψ' production. We observe an overlap region in p(⊥) where our results match smoothly to those obtained in a next-to-leading order collinearly factorized NRQCD formalism. The relative contribution of color singlet and color octet contributions can be quantified in the CGC+NRQCD framework, with the former contributing approximately 10% of the total cross section.
We propose a novel method to compute multi-loop master integrals by constructing and numerically solving a system of ordinary differential equations, with almost trivial boundary conditions. Thus it ...can be systematically applied to problems with arbitrary kinematic configurations. Numerical tests show that our method can not only achieve results with high precision, but also be much faster than the only existing systematic method sector decomposition. As a by product, we find a new strategy to compute scalar one-loop integrals without reducing them to master integrals.
•Friction stir processing leads to significant enhancement in corrosion resistance of AZ91alloy.•Corrosion behavior is evaluated by electrochemical, hydrogen evolution and mass loss measurements.•The ...effect of microstructure modification on the corrosion behavior is analyzed.•Beneficial effect of texture and stable β layer on corrosion resistance is documented.
Friction stir processing (FSP) is applied to modify the surface microstructure of cast AZ91 magnesium alloy. The electrochemical and hydrogen evolution measurements reveal that the corrosion rate of processed alloy in 3.5 wt% NaCl solution is significantly decreased. This is mainly attributed to the alteration of corrosion process induced by modification on the morphology and distribution of β-Mg17Al12 phase via FSP. It is originally reported that the formation of a compact and continuous β phase layer on the FSPed surface owing to the segregation of fine β phase effectively enhances the stability and passivity of corrosion product film.
The coronavirus disease 2019 pandemic caused by the novel coronavirus SARS‐CoV‐2 (severe acute respiratory syndrome coronavirus 2) has claimed many lives worldwide. Wearing medical masks (MMs) or N95 ...masks (N95Ms namely N95 respirators) can slow the virus spread and reduce the infection risk. Reuse of these masks can minimize waste, protect the environment, and help solve the current imminent shortage of masks. Disinfection of used masks is needed for their reuse with safety, but improper decontamination can damage the blocking structure of masks. In this study, we demonstrated using the avian coronavirus of infectious bronchitis virus to mimic SARS‐CoV‐2 that MMs and N95Ms retained their blocking efficacy even after being steamed on boiling water for 2 hours. We also demonstrated that three brands of MMs blocked over 99% viruses in aerosols. The avian coronavirus was completely inactivated after being steamed for 5 minutes. Altogether, this study suggested that MMs are adequate for use on most social occasions and both MMs and N95Ms can be reused for a few days with steam decontamination between use.
Highlights
Reuse of medical masks and N95 respirators is highly needed.
The masks have excellent efficacy in blocking coronaviruses in aerosols.
The masks should be decontaminated for reuse.
The masks maintain their blocking efficacy after being steamed on boiling water.
The steam measure can inactivate coronaviruses completely.
ABSTRACT
Due to the non-linear ionizing and heating processes, the 21-cm signals from epoch of reionization (EoR) are expected to have strong non-Gaussian fluctuations. In this paper, we use the ...seminumerical simulations to study the non-Gaussian statistics, i.e. skew spectrum and smoothed skewness of the 21-cm signals from EoR. We find the 21-cm skew spectrum and smoothed skewness have similar evolution features with the 21-cm bispectrum. All of them are sensitive to the EoR models, while not too much to the cosmic volume applied. With the SKA1-low telescope as reference, we find both the skew spectrum and smoothed skewness have much higher signal-to-noise ratios than the 21-cm bispectrum.
► Five 3-D hydrate samples are formed to study CH4–CO2 replacement with liquid CO2. ► Liquid CO2 adapts to hydrate reservoirs with/without underlying gas or free water. ► CH4 replacement rate and ...amount increase with the increase of hydrate saturation. ► Saturations of water and hydrate have different effect on CH4 replacement percent. ► There exists a phase zone that replacement rate and percent of CH4 are higher.
The dynamics of CH4 replacement in natural gas hydrate with liquid CO2 was studied with a high pressure three-dimensional reactor. Five groups of hydrate samples were formed to investigate the effect of hydrate reservoir properties on CH4–CO2 replacement reaction. The results showed that CH4 in the hydrate gradually moves to the liquid CO2 phase while CO2 in the liquid phase penetrates into the hydrate under pressure–temperature conditions not only within the phase zone surrounded by (LCO2–VCO2), (water–HCO2–LCO2), and (water–HCH4–VCH4) curves but also that above (LCO2–VCO2) and (water–HCH4–VCH4) curves. The replacement rate and amount of CH4 increase with the increase of hydrate saturation in the sediments. Compared with injecting gaseous CO2 method, liquid CO2 injection is also benefit for the recovery of CH4 from hydrate reservoir with much free water or that without underlying gas room to the extent that the injection of liquid CO2 is kept by high gas saturation. The replacement percent of CH4 hydrate decreases with the increase of hydrate saturation, but increases with the increase of water saturation. A higher replacement percent is obtained in the zone surrounded by three phase curves of (LCO2–VCO2), (water–HCO2–LCO2) and (water–HCH4–VCH4).
Graphene-based materials with aerogel structures were developed in recent years for various adsorption applications. In the present study, a hydrothermal process was developed to prepare graphene ...aerogel by using graphene oxide as a precursor, and the obtained aerogel was employed as a template for the growth of carbon nanotubes (CNTs). Various techniques were employed to study the morphology, surface property and composition of aerogel samples. The results showed that CNTs were in-situ grown on the sheet of graphene aerogel, endowing the material a hierarchical structure with enhanced surface area and meso- and micro-scale pores. These improved properties made the hybrid aerogel a superior material for the selective adsorption of a variety of organics and oils from water.
A hybrid aerogel consisting of carbon nanotubes (CNTs) and graphene was prepared. The growth of CNTs on the graphene sheets in the hybrid aerogel endowed the material a hierarchical structure with low density, excellent hydrophobicity and oleophilicity to the organic compounds. The aerogel can adsorb a variety of oily liquids with outstanding reusability. Display omitted
PDF
