As the most promising lead‐free branch, tin halide perovskites suffer from the severe oxidation from Sn2+ to Sn4+, which results in the unsatisfactory conversion efficiency far from what they ...deserve. In this work, by facile incorporation of methylammonium bromide in composition engineering, formamidinium and methylammonium mixed cations tin halide perovskite films with ultrahighly oriented crystallization are synthesized with the preferential facet of (001), and that oxidation is suppressed with obviously declined trap density. MA+ ions are responsible for that impressive orientation while Br‐ ions account for their bandgap modulation. Depending on high quality of the optimal MA0.25FA0.75SnI2.75Br0.25 perovskite films, their device conversion efficiency surges to 9.31% in contrast to 5.02% of the control formamidinium tin triiodide perovskite (FASnI3) device, along with almost eliminated hysteresis. That also results in the outstanding device stability, maintaining above 80% of the initial efficiency after 300 h of light soaking while the control FASnI3 device fails within 120 h. This paper definitely paves a facile and effective way to develop high‐efficiency tin halide perovskites solar cells, optoelectronic devices, and beyond.
MABr induces the remarkably oriented growth of tin halide perovskite films (MAxFA1−xSnI3−xBrx) by alloying, which results in an optimal device conversion efficiency of 9.31% enhanced from 5.02% of the pristine FASnI3 device and maintained above 80% of the initial efficiency after 300 h light soaking while the control device fails within 120 h.
In this work, an insight into the premature Type IV cracking was undertaken to clarify its mechanisms in Grade 91 steel pipe weldments. High-resolution microscopy observations of the as-welded ...heat-affected zone (HAZ) reveal that the commonly recognized fine-grained region susceptible of cracking on the edge of HAZ belongs to the inter-critical HAZ (ICHAZ), rather than the fine-grained HAZ (FGHAZ). Instrumented indentation tests uncover that the ICHAZ is the weakest region across the weld, exhibiting the largest displacement and the lowest hardness in three thermal stages. Localized deformation of matrix grains and high stress triaxiality in the ICHAZ promoted nucleation of creep cavities along grain boundaries. This localized deformation was induced by the creep strength mismatch of matrix grains with different Cr concentrations. Cavity-free regions exhibit a relatively homogenous Cr distribution, whereas, an inhomogeneous Cr distribution is observed in the cavity-containing regions. It is believed that this local Cr inhomogeneity in the ICHAZ is caused by the partial dissolution of Cr-rich M23C6 carbides and an insufficient homogenization during rapid welding thermal cycles.
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•Heterogenous fine-grained strucuture belonging to the intercritical heat-affected zone degraded faster than the other regions.•Localized C and Cr inhomogeneities in the matrix weakened intercritical heat-affected zone.•Localized high stress triaxiality around coarsened precipitates induced cavity nucleation at the triple juctions of grain boundaries.
The Corona Virus Disease 2019 (COVID-19) pandemic resulting from the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has led to significant morbidity and mortality in patients and put a ...strain on healthcare systems worldwide. The clinical characteristics and results of COVID-19 in immunosuppressed patients, such as people living with human immunodeficiency virus (PLWH), considered at higher risk of severe disease, are not well-characterized. Accumulated evidence indicates that COVID-19 and the human immunodeficiency virus (HIV) can interact in various ways. This review explored the similarities and differences in virology between SARS-CoV-2 and HIV, the effect of the COVID-19 vaccine on PLWH, the impact of the COVID-19 pandemic on PLWH care and prevention, and the influence of HIV-related factors on COVID-19. Discovering the potential link between HIV and COVID-19 may provide a novel way to avoid the factors of HIV and SARS-CoV-2 co-infection and advance future research.
To investigate the effect of the organic loading rate (OLR) on anaerobic treatment of monosodium glutamate (MSG) wastewater, a lab-scale up-flow anaerobic blanket (UASB) reactor was continuously ...operated over a 222-day period. The overall performances of COD removal and methane recovery initially exhibited an increase and subsequently decreased when the OLR was increased from 1 g-COD/L/d to 24 g-COD/L/d. At the optimal OLR of 8 g-COD/L/d, superior performance was obtained with a maximum COD removal efficiency of 97%, a methane production rate of 2.3 L/L/d, and specific methanogenic activity of 86 mg-CH4/g-VSS/d (feeding on glutamate), with superior characteristics of sludge in VSS concentration, average diameter of granules, and settling velocity. According to the results of the specific methanogenic activity, the methanogenic pathway was more inclined to pass through acetate than through hydrogen. Methanosarcina instead of Methanosaeta, with Methanobacterium and greatly increased Firmicutes, dominated in the UASB reactor after long term operation. These results support that the OLR had a substantial effect on both the treatment and energy recovery efficiency of MSG wastewater as well as on microbial community variations in the UASB reactor.
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•Methanogenic degradation of monosodium glutamate wastewater was validated.•Optimal COD removal and CH4 recovery performance was obtained at OLR below 8 g/L/d.•Maximal glutamate removal capacity of the UASB reactor reached 18 g-COD/L/d.•Methanobacterium and Methanosarcina were dominated after long-term operation.•The OLR had a substantial impact on the microbial community variations in the UASB.
Negative behaviors at the workplace always disturb the management of the firms. This research investigates the link between the dark triad and various types of Knowledge hiding (Evasive hiding, ...Playing dumb, and Rationalized hiding) in firms. In addition, this study explores perceived organizational politics as a mediator. The design of this study is quantitative and positivist. The data were collected in three waves (45 days gap) with a random sampling approach from 383 personnel/staff working in Chinese commercial banking firms. The data were analyzed using the partial least squares structural equation modeling (PLS-SEM) technique and Smartpls-4 software. This study confirms that dark-triad has a positive relation with knowledge hiding, except psychopathy and Machiavellianism, which have no significant correlation with playing dumb and evasive hiding, respectively. Perceived organizational politics significantly mediate the association between dark triad personality traits and the types of knowledge hiding. Employees with political skills and a trust-based culture can counter the dark-triad personalities and discourage the knowledge-hiding culture. For effective management of knowledge-hiding issues in firms, codifying implicit and explicit Knowledge and developing knowledge repositories can discourage a knowledge-hiding culture.
A cytocompatible porous scaffold mimicking the properties of extracellular matrices (ECMs) has great potential in promoting cellular attachment and proliferation for tissue regeneration. A biomimetic ...scaffold was prepared using silk fibroin (SF)/sodium alginate (SA) in which regular and uniform pore morphology can be formed through a facile freeze-dried method. The scanning electron microscopy (SEM) studies showed the presence of interconnected pores, mostly spread over the entire scaffold with pore diameter around 54~532 μm and porosity 66~94%. With significantly better water stability and high swelling ratios, the blend scaffolds crosslinked by 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDC) provided sufficient time for the formation of neo-tissue and ECMs during tissue regeneration. Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD) results confirmed random coil structure and silk I conformation were maintained in the blend scaffolds. What's more, FI-TR spectra demonstrated crosslinking reactions occurred actually among EDC, SF and SA macromolecules, which kept integrity of the scaffolds under physiological environment. The suitable pore structure and improved equilibrium swelling capacity of this scaffold could imitate biochemical cues of natural skin ECMs for guiding spatial organization and proliferation of cells in vitro, indicating its potential candidate material for soft tissue engineering.
Data on the longitudinal association of walking pace with the risk of cognitive decline and dementia are inconsistent and inconclusive. Therefore, researchers conducted a meta-analysis of prospective ...cohort studies to quantitatively assess the association of walking pace with the risk of cognitive decline and dementia among elderly populations.
Eligible studies were searched in PubMed and EMBASE through April 22, 2016. Additional information was retrieved through Google Scholar or hand review of the reference lists from the relevant studies. Prospective cohort studies were included if they reported relative risk (RR) and the corresponding 95% confidence interval (CI) of cognitive decline or dementia in relation to walking pace.
Seventeen studies were identified, including 10 studies reporting the RR of cognitive decline (9,949 participants and 2,547 events) and 10 presenting the RR of dementia (14,140 participants and 1,903 events). Comparing the lowest to the highest category of walking pace, the pooled RR was 1.89 (95% CI = 1.54-2.31) for cognitive decline and 1.66 (95% CI = 1.43-1.92) for dementia. With every 1 dm/s (360 m/h) decrement in walking pace, the risk of dementia was increased by 13% (RR = 1.13; 95% CI = 1.08-1.18).
This meta-analysis provides accumulated evidence supporting that slow or decreased walking pace is significantly associated with elevated risk of cognitive decline and dementia in elderly populations.
The purpose of this study is to determine the effect of augmented reality (AR) applications on K-12 students' academic achievement through meta-analysis and thematic analysis. 40 samples from 35 ...articles published between 2006 and 2020 were used to examine the impact of AR on academic achievement and to explore the effects of differences in grade level, academic subject, duration of the experiment, and sampling methods. The research results showed that (1) AR has a medium effect on K-12 students' academic achievement (g = 0.437) according to the Thalheimer and Cook's effect size classification. (2) academic subject and duration of experiment as moderator variables have a significant influence on whether AR application will enhance K-12 students' academic achievement, and (3) the advantages of AR in K-12 education include enhancing interest and motivation, offering vivid resources, providing an interactive environment, and improving attention. The disadvantages include integrated method limitations, system function shortcomings, and the causing of physical discomfort problems. The advantages and disadvantages show why AR application has a medium effect on K-12 students' academic achievement.
Developing greener batteries with new chemistries is a formidable challenge, and a major focus for years to come. Redox flow batteries are receiving increasing research interest for grid-scale ...electrochemical energy storage owing to their unique architecture. However, challenges still remain by their low energy density as well as corrosive and/or toxic electrolytes. An anolyte based on aprotic Zn deep-eutectic-solvent, which uses low cost, abundant and environmentally benign materials, exhibits a utilizable concentration of Zn
ca. 1.7 M, resulting in a reversible volumetric capacity of ca. 90 A h·L
. Combined with high efficiencies and relatively low redox potential of -1.12 V vs. Ag/AgCl, such an anolyte provides an alternative way to explore a family of anolytes using new chemistries for rechargeable Zn batteries that meet the criteria for grid-scale electrical energy storage.
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•Remaining lifetime of service-aged forge 91-pipe 91 steel header was assessed with novel analytical testing tools.•A new feature full-size cross-weld creep specimen including the ...entire weld thickness was successfully designed and evaluated.•Non-uniform localized creep deformation in multi-pass welds was visualized and quantified using in-situ digital image correlation.•The threshold strain and fracture criteria of the service-aged header were determined with the measured localized creep strain in heat affected zone.•The high number of inclusions was the dominating metallurgical risk responsible for the faster creep strength degradation on the forge 91 steel side.
Condition assessment of welded steam components is a crucial activity for safe power plant operations. In this work, remaining lifetime of a 141,000-hour service-aged large bore girth weld between an SA-182 forged 91 (F91) reducer and an SA-335 pipe 91 (P91) header was assessed with a specially designed in-situ high temperature digital image correlation (DIC) system. Nonuniform creep deformation/damages in this service-aged multi-pass F91-P91 welds were quantified and characterized. The in-situ DIC strain measurements reveal the nominal creep strain averaged over the gauge length was consistently below 3%, and the localized creep strain value at failure in the HAZ was ∼10%. Advanced metallurgical characterization was executed in the as-received and posttest conditions to determine the contributions of preexisting creep damage, the so-called “soft zone” in the HAZ, and microstructural variations in the HAZ to the observed Type IV failure. Creep failure occurred in the most predamaged region and this location is adjacent to, but not inside, the documented soft zone before the test. The higher fraction of inclusions in F91 steel contributed significantly to the lower creep resistance observed in both base metal and HAZ.
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