The introduction of the concept of valley pseudospin to phononic crystals has made a remarkable topologically protected interface transport of sound, which opens a novel research area referred to as ...valley Hall topological insulators. Here, we demonstrate the simultaneous multi-band edge states of shear vertical waves in two-dimensional phononic crystals with veins. The multi-band edge states are topologically valley-protected and are obtained by simultaneously gapping multiple Dirac points at K (or K') under the inversion symmetry breaking. As the relative radius of the two adjacent steel columns varies, the band diagram undergoes a topological transition which can be characterized by topological charge distributions and opposite valley Chern numbers. Subsequently, the vortex chirality of the bulk valley modes is unveiled. With numerical simulations, simultaneous multi-band valley dependent edge states and the associated valley-protected backscattering suppression around the curved waveguide are further demonstrated. Our work could become a promising platform for applications of multi-functional topological acoustic devices.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
The pore dimension and surface property directly dictate the transport of guests, endowing diverse gas selective adsorptions to porous materials. It is highly relevant to construct metal−organic ...frameworks (MOFs) with designable functional groups that can achieve feasible pore regulation to improve their separation performances. However, the role of functionalization in different positions or degrees within framework on the separation of light hydrocarbon has rarely been emphasized. In this context, four isoreticular MOFs (TKL‐104−107) bearing dissimilar fluorination are rationally screened out and afforded intriguing differences in the adsorption behavior of C2H6 and C2H4. Ortho‐fluoridation of carboxyl allows TKL‐105−107 to exhibit enhanced structural stabilities, impressive C2H6 adsorption capacities (>125 cm3 g−1) and desirable inverse selectivities (C2H6 over C2H4). The more modified ortho‐fluorine group and meta‐fluorine group of carboxyl have improved the C2H6/C2H4 selectivity and adsorption capacity, respectively, and the C2H6/C2H4 separation potential can be well optimized via linker fine‐fluorination. Meanwhile, dynamic breakthrough experiments proved that TKL‐105−107 can be used as highly efficient C2H6‐selective adsorbents for C2H4 purification. This work highlights that the purposeful functionalization of pore surfaces facilitates the assembly of highly efficient MOF adsorbents for specific gas separation.
The C2H6/C2H4 separation potential is successfully optimized by virtue of linker fine‐fluorination within an isoreticular cadmium‐organic framework platform. Due to the integrated balance between adsorption selectivity and capacity, fluorinated TKL‐105−107 exhibit distinct one‐step ethylene purification capabilities from C2H6/C2H4 mixtures, shedding light on the effect of tailor‐made fluorine functionalization on the advanced separation/purification applications.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Past studies have suggested that ozone in the troposphere has increased globally throughout much of the 20th century due to increases in anthropogenic emissions and transport. We show, by combining ...satellite measurements with a chemical transport model, that during the last four decades tropospheric ozone does indeed indicate increases that are global in nature, yet still highly regional. Satellite ozone measurements from Nimbus-7 and Earth Probe Total Ozone Mapping Spectrometer (TOMS) are merged with ozone measurements from the Aura Ozone Monitoring Instrument/Microwave Limb Sounder (OMI/MLS) to determine trends in tropospheric ozone for 1979–2016. Both TOMS (1979–2005) and OMI/MLS (2005–2016) depict large increases in tropospheric ozone from the Near East to India and East Asia and further eastward over the Pacific Ocean. The 38-year merged satellite record shows total net change over this region of about +6 to +7 Dobson units (DU) (i.e., ∼15 %–20 % of average background ozone), with the largest increase (∼4 DU) occurring during the 2005–2016 Aura period. The Global Modeling Initiative (GMI) chemical transport model with time-varying emissions is used to aid in the interpretation of tropospheric ozone trends for 1980–2016. The GMI simulation for the combined record also depicts the greatest increases of +6 to +7 DU over India and East Asia, very similar to the satellite measurements. In regions of significant increases in tropospheric column ozone (TCO) the trends are a factor of 2–2.5 larger for the Aura record when compared to the earlier TOMS record; for India and East Asia the trends in TCO for both GMI and satellite measurements are ∼+3 DU decade(exp −1) or greater during 2005–2016 compared to about +1.2 to +1.4 DU decade(exp −1) for 1979–2005. The GMI simulation and satellite data also reveal a tropospheric ozone increases in ∼+4 to +5 DU for the 38-year record over central Africa and the tropical Atlantic Ocean. Both the GMI simulation and satellite-measured tropospheric ozone during the latter Aura time period show increases of ∼+3 DU decade−1 over the N Atlantic and NE Pacific.
We report a hierarchical first-principles investigation on the entangled effects of lattice dimensionality and bond characteristics in the lattice dynamics of silicene and germanene. It is found that ...bond bending (stretching) negatively (positively) contributes to Gruneisen constant gamma , which results in the negative acoustic (positive optical) gamma . The layer thickening (bond weakening) caused by chemical functionalization tends to increase (decrease) the acoustic (optical) gamma , due to the increased (decreased) bond-stretching effect. The excitation of the negative- gamma modes results in negative thermal expansion, while mode excitation and thermal expansion compete with each other in thermomechanics. The sensitive structural and electronic responses of silicene and germanene to functionalization help us to derive a generic physical picture for two-dimensional lattice dynamics.
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CMK, CTK, FMFMET, IJS, NUK, PNG, UM
While artificial intelligence-based chatbots have demonstrated great potential for writing, little is known about whether and how doctoral students accept the use of ChatGPT in writing. Framed with ...Technology Acceptance Model, this study investigated doctoral students’ acceptance toward ChatGPT in writing and the factors that influence it. The questionnaire survey revealed a high intention to use ChatGPT in writing among doctoral students in China. The findings further indicated that attitude was a significant predictor of behavioural intention to use ChatGPT in writing and mediated the impacts of perceived usefulness and perceived ease of use on it. Perceived ease of ChatGPT use was in turn influenced by students’ past ChatGPT use experience. This study provides powerful evidence for the applicability of Technology Acceptance Model in the acceptance of ChatGPT in writing. The results have significant implications for leveraging ChatGPT for writing in higher education.
Semiconductor quantum dots (QDs) are the most versatile fluorophores for Förster resonance energy transfer (FRET) because they can function as both donors and acceptors for a multitude of ...fluorophores. However, a complete understanding of multidonor–multiacceptor FRET networks on QDs and their full employment into advanced fluorescence sensing and imaging have not been accomplished. Here, we provide a holistic photophysical analysis of such multidonor-QD-multiacceptor FRET systems using time-resolved and steady-state photoluminescence (PL) spectroscopy and Monte Carlo simulations. Multiple terbium complex (Tb) donors (1–191 units) and Cy5.5 dye acceptors (1–60 units) were attached to a central QD, and the entire range of combinations of FRET pathways was investigated by Tb, QD, and Cy5.5 PL. Experimental and simulation results were in excellent agreement and could disentangle the distinct contributions of hetero-FRET, homo-FRET, and dye dimerization. The FRET efficiency was independent of the number of Tb donors and dependent on the number of Cy5.5 acceptors, which could be used to independently adapt the PL intensity by the number of Tb donors and the PL lifetime by the number of Cy5.5 acceptors. We used this unique tuning capability to prepare Tb-QD-Cy5.5 conjugates with distinct QD PL lifetimes but similar QD PL intensities. These brightness-equalized multihybrid FRET nanoparticles were applied to optical barcoding via three time-gated PL intensity detection windows, which resulted in simple RGB ratios. Direct applicability was demonstrated by an efficient RGB distinction of different nanoparticle-encoded microbeads within the same field of view with both single-wavelength excitation and detection on a standard fluorescence microscope.
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IJS, KILJ, NUK, PNG, UL, UM
Sugarcane, a C
plant, provides most of the world's sugar, and a substantial amount of renewable bioenergy, due to its unique sugar-accumulating and feedstock properties. Brazil, India, China, and ...Thailand are the four largest sugarcane producers worldwide, and the crop has the potential to be grown in arid and semi-arid regions if its stress tolerance can be improved. Modern sugarcane cultivars which exhibit a greater extent of polyploidy and agronomically important traits, such as high sugar concentration, biomass production, and stress tolerance, are regulated by complex mechanisms. Molecular techniques have revolutionized our understanding of the interactions between genes, proteins, and metabolites, and have aided in the identification of the key regulators of diverse traits. This review discusses various molecular techniques for dissecting the mechanisms underlying the sugarcane response to biotic and abiotic stresses. The comprehensive characterization of sugarcane's response to various stresses will provide targets and resources for sugarcane crop improvement.
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ObjectiveTo investigate the relationship between job satisfaction, work stress, work–family conflict and turnover intention, and explore factors associated with turnover intention, among physicians ...in Guangdong Province, China.MethodsFrom August to October 2013, physicians completed questionnaires and scales with regard to their job satisfaction, work stress, work–family conflict, and turnover intention. Binary logistic regression and structural equation modelling (SEM) were used in data analysis.ResultsA total of 3963 physicians were approached, with 3563 completing the questionnaire. The mean score of the overall perception of turnover intention of physicians who worked in Guangdong was 2.71 on a scale ranging from 1 to 6. Hours worked per week, working in an urban/rural area, type of institution, and age significantly impacted on turnover intention. Turnover intention was directly and negatively related to job satisfaction, and it was directly, indirectly and positively related to work stress and work–family conflict.ConclusionJob satisfaction, work stress, work–family conflict, hours worked per week, working in an urban/rural area, types of institution and age are influencing factors of turnover intention. Reducing working hours, raising salary, providing more opportunities for career development and training, supporting and encouraging physicians by senior managers could potentially contribute to the reduction in turnover intention.
Copper is coated on indium-tin-oxide (ITO) thin film to improve its electrical resistivity. In order to recycle the scrap Cu/ITO thin film, an ionic liquid (1-butyl-3-methyl imidazolium ...hexafluorophosphate (C4mimPF6)) containing iodine/iodide (IL-I) was used to extract copper at 303, 343, 413, 374, and 543 K. The extraction efficiency of copper from the scrap Cu/ITO thin film was >99% with IL-I. Using XRD, crystal In2O3 was found on the regenerated ITO thin film which had a resistivity similar to that of unused ITO thin film. Using X-ray absorption near edge structural (XANES) spectroscopy, at least two paths for the extraction of copper from the Cu/ITO thin film into IL-I were identified. Path I: Copper is stripped from the scrap Cu/ITO thin film and then interacts with I3− in the IL-I to form nano CuI. The nano CuI further interacts with I−. Path II: Copper interacts with I3− on the surface of the Cu/ITO thin film to form nano CuI. The nano CuI is further stripped into the IL-I to interact with I−. During extraction, the nanoparticle size could be increased in the IL-I by conglomeration due to fewer coordinating anions and decrease in the viscosity of IL-I at high temperatures. Furthermore, nanoparticle growth was affected by PF6− of the IL-I determined via 31P NMR.
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