Efficient Green Quasi-Two-Dimensional Perovskite Light-Emitting Diodes Based on Mix-Interlayer

Recently, quasi-two-dimensional (Q-2D) perovskites have received much attention due to their excellent photophysical properties. Phase compositions in Q-2D perovskites have obvious effect on the device performance. Here, efficient green perovskite light-emitting diodes (PeLEDs) were fabricated by employing o-fluorophenylethylammonium bromide (o-F-PEABr) and 2-aminoethanol hydrobromide (EOABr) as the mix-interlayer ligands. Phase compositions are rationally optimized through composition and interlayer engineering. Meanwhile, non-radiative recombination is greatly suppressed by the introduction of mix-interlayer ligands. Thus, green PeLEDs with a peak photoluminescence quantum yield (PLQY) of 81.4%, a narrow full width at half maximum (FWHM) of 19 nm, a maximum current efficiency (CE) of 27.7 cd/A, and a maximum external quantum efficiency (EQE) of 10.4% were realized. The results are expected to offer a feasible method to realize high-efficiency PeLEDs.

Effect of Aluminum Incorporation on the Reaction Process and Reaction Products of Hydrated Magnesium Silicate

In this study, we investigated the impact of aluminium ion (Al3+) incorporation on the microstructure and the phase transformation of the magnesium silicate hydrate system. The magnesium silicate hydrate system with aluminium was prepared by mixing magnesium oxide and silica fume with different aluminium ion contents (the Al/Si molar ratios of 0.01, 0.02, 0.05, 0.1, 0.2) at room temperature. The high degree of polymerization of the magnesium silicate hydrate phases resulted in the limited incorporation of aluminium in the structure of magnesium silicate hydrate. The silicon-oxygen tetrahedra sites of magnesium silicate hydrate layers, however, were unable to substitute for silicon sites through inverted silicon-oxygen linkages. The increase in aluminium ion content raised the degree of polymerization of the magnesium silicate hydrate phases from 0.84 to 0.92. A solid solution was formed from residual aluminum-amorphous phases such as hydroxyl-aluminum and magnesium silicate hydrate phases. X-ray diffraction (XRD), field emission scanning electron microscope (F-SEM), and 29Si and 27Al MAS NMR data showed that the addition of Al3+ promotes the hydration process of MgO and has an obvious effect on the appearance of M-S-H gel. The gel with low aluminum content is fluffy, while the gel with high aluminum content has irregular flakes. The amount of Al3+ that enters the M-S-H gel increased with the increase of Al3+ content, but there was a threshold: the highest Al/Si molar ratio of M-S-H gel can be maintained at about 0.006.

Analysis of Situ Test Results of Earth Pressure and Pile Internal Force under Pile-Anchor Support in a Deep Foundation Pit in Xi’an

At present, in deep foundation pit engineering, on the one hand, practice is ahead of theory, and on the other hand, theory can not correctly reflect the actual construction process and environmental effects. In order to further study the distribution and change law of earth pressure and internal force of pile body in deep foundation pit pile-anchor supporting system, field monitoring test of earth pressure and pile body reinforcement stress was carried out. The monitoring results show that before excavation, the distribution of earth pressure has a great relationship with the layering of the soil, and it is distributed in sections along the depth. Compared with the theoretical static earth pressure, the measured data of the upper depth is relatively small; after excavation, the overall earth pressure is distributed along the depth in a “z” shape under the non-limiting state. As the excavation progresses, the magnitude of the reduction of the earth pressure varies from place to place, and the magnitude of the decrease of the soil with better properties is not large; after the excavation, the stress and earth pressure of the pile reinforcement correspond to each other, and the distribution is also nonlinear. The existence of anchor tension has an obvious effect on improving the internal force of the pile. The selected earth pressure calculation methods have some discrepancies in the calculation of the earth pressure value of the project, and they need to be further improved. The research in this paper can provide reference and reference for the calculation of earth pressure and support design of pile-anchor supported foundation pit.

A rare form of intoxication: acute methyl ethyl ketone peroxide poisoning

We report two suicidal cases of acute methyl ethyl ketone peroxide (MEKP) poisoning. A woman in her late 60s suffered from oral mucosal erosion, functional impairment of the heart, liver and other organs, pulmonary inflammation, elevated inflammatory markers, pleural effusion, hypoproteinemia and metabolic acidosis after oral administration of approximately 50 mL of MEKP. After admission, the patient was administered hemoperfusion four times, 8 mg of betamethasone for 6 days and symptomatic support. Hemoperfusion had an obvious effect on the treatment of oral MEKP poisoning. After discharge, the patient developed progressive dysphagia and secondary esophageal stenosis. Supplementary feeding was administered with a gastrostomy tube after the patient was completely unable to eat. A man in his mid-40s developed oropharyngeal mucosal erosion, bronchitis and esophageal wall thickening after oral administration of 40 ml MEKP. After receiving total gastrointestinal dispersal, 80 mg of methylprednisolone was administered for 7 days, and symptomatic supportive treatment was provided. Slight dysphagia was observed after discharge, and there was no major effect on the quality of life. Patients with acute oral MEKP poisoning should be followed up regularly to observe its long-term effects on digestive tract corrosion and stenosis.

Effects of the highway live load on the additional forces of the continuously welded rails of a long-span suspension bridge

High-speed running trains have higher regularity requirements for rail tracks. The track-bridge interaction of long-span bridges for high-speed railways has become a key factor for engineers and researchers in the last decade. However, studies on the track-bridge interaction of long-span bridges are rare because the bridges constructed for high-speed railways are mainly short- or moderate-span bridges, and the effects of the highway live load on the additional forces of continuously welded rails (CWRs) have not been reported. In the present study, the effects of the highway live load on the additional forces of a CWR of a long-span suspension bridge are investigated through numerical simulations. A track-bridge spatial analysis model was established using the principle of the double-layer spring model and the bilinear resistance model. The additional stress and displacement of the rail are calculated, and the effects of the highway live load are analyzed and compared with those without a highway live load. The results show that the highway live load has an obvious effect on the additional forces of a CWR. Under a temperature force, the highway live load increases the maximum tensile stress and compressive stress by 10 and 13%, respectively. Under a bending force, the highway live load increases the maximum compressive rail stress and maximum displacement by 50 and 54%, respectively. Under a rail breaking force, when the highway live load is taken into consideration, the rail displacement at both sides of the broken rail varies by 50 and 42%, respectively. The highway live load must be taken into consideration when calculating the additional forces of rails on highway-railway long-span bridges.

An experiment on full-day power generation building fabric component for zero-energy buildings

Thermal electricity generation (TEG) is a potential method to utilize energy emitted from the built environment. This work presents a prototype of the low-cost full-day power generation solar building component, which can be integrated as the building fabric or as a part of the solar panels. The size of the prototype is 0.04 m2. The overall cost is less than 25 USD. The prototype is tested in various environments to validate its performance. The first experiment tests its performance under the radiation of a high-temperature source, the prototype can generate the highest voltage of 0.8 V. In onsite experiments, it can reach a maximum value of 10 mW/m2 under sunlight. It can also work at night depending on the thermal radiation of the environment. It can also be used in different weather; the performance is even better than the nighttime. The experiments indicate that radiation heat transfer has a stronger influence on energy conversion than the convective heat transfer. The relative humidity has a certain influence on its performance, but there is no obvious effect of radiation heat transfer. Although the prototype has great potential, there are still limitations, and this article also discusses the problems. Meanwhile, this article also points out possible directions for improving design in the future. The results in this article might be helpful for zero-energy buildings and low-carbon buildings.

Research on the performance of two different porphin graphene nanoribbons coupled thermoelectric devices

The effect of bonding position on the energy conversion efficiency of porphin graphene nanoribbons coupled thermoelectric devices was studied by the first-principles. The results show that the change of bonding position can greatly adjust the lattice thermal conductivity of the coupled thermoelectric devices; although the change of bonding position has no obvious effect on the transport properties of holes in the coupled structure, it can obviously adjust the transport properties of electrons, resulting in the different Seebeck coefficients and quality merit values of different coupled thermoelectric devices The results illustrate the different thermoelectric energy conversion effects in different porphin graphene nanoribbons coupled thermoelectric devices with different bonding positions, which provides an effective theoretical basis for the design of thermoelectric quantum devices based on graphene nanoribbons.

The Impact of Health and Wealth on Settlement Intention of Migrants: The Moderating Effect of Social Welfare

Background: With the rapid urbanization, citizenization of migrants is becoming the development tendency in China. It is significant to analyze the determining factors of the settlement intention of migrants.Methods: The data we used were taken from the China Migrants Dynamic Survey (CMDS) in 2017. Multilevel mixed-effects logistic regression was used to analyze the relationship between air pollution, economic advantages, and settlement intention between different migrants and the moderating effect of social welfare.Results: At the individual level, being female, married, urban and other ethnic, having higher education, older, and health associated with likelihood of settlement intention of migrants. Higher health education, social integration, and, have a health record were positively associated with the likelihood of settlement intention. Higher educated, urban areas, and Han migrants were willing to reduce their pursuit of health for economic development.Conclusion: Health education and more social organizational participation can reduce the negative effect of air pollution and increase the positive effect of economic advantages on settlement intention of migrants. But, in less economically advantaged areas, it has no obvious effect. In the choice of health and wealth, the settlement intention of migrants shows difference, and unfairness and social welfare, in particular health education, can narrow this difference.

Relationships between Burn Severity and Environmental Drivers in the Temperate Coniferous Forest of Northern China

Burn severity is a key component of fire regimes and is critical for quantifying fires’ impacts on key ecological processes. The spatial and temporal distribution characteristics of forest burn severity are closely related to its environmental drivers prior to the fire occurrence. The temperate coniferous forest of northern China is an important part of China’s forest resources and has suffered frequent forest fires in recent years. However, the understanding of environmental drivers controlling burn severity in this fire-prone region is still limited. To fill the gap, spatial pattern metrics including pre-fire fuel variables (tree canopy cover (TCC), normalized difference vegetation index (NDVI), and live fuel moisture content (LFMC)), topographic variables (elevation, slope, and topographic radiation aspect index (TRASP)), and weather variables (relative humidity, maximum air temperature, cumulative precipitation, and maximum wind speed) were correlated with a remote sensing-derived burn severity index, the composite burn index (CBI). A random forest (RF) machine learning algorithm was applied to reveal the relative importance of the environmental drivers mentioned above to burn severity for a fire. The model achieved CBI prediction accuracy with a correlation coefficient (R) equal to 0.76, root mean square error (RMSE) equal to 0.16, and fitting line slope equal to 0.64. The results showed that burn severity was mostly influenced by flammable live fuels and LFMC. The elevation was the most important topographic driver, and meteorological variables had no obvious effect on burn severity. Our findings suggest that in addition to conducting strategic fuel reduction management activities, planning the landscapes with fire-resistant plants with higher LFMC when possible (e.g., “Green firebreaks”) is also indispensable for lowering the burn severity caused by wildfires in the temperate coniferous forests of northern China.

U(VI) Adsorption onto Low Dose Radiation Acclimated Tradescantia Fluminensis

The plants that long-term grown in radiation area could be acclimated by low dose radiation (LDR). In this paper, LDR acclimated Tradescantia fluminensis (Commelinaceae) was first collected as a biomass adsorbent towards uranium adsorption. Comparative experiments verified the potential radiation effects of LDR acclimation, moreover, qe values of the wild and LDR acclimated Tradescantia fluminensis were ~16 mg/g and 20 mg/g, respectively. U(VI) adsorption amount gradually reached equilibrium after 180 min shaking, and the adsorption process described well by the pseudo-second-order model. However, ionic strength has no obvious effect on the qe values. SEM and TG-DSC suggested good structural stability of LDR acclimated Tradescantia fluminensis during the U(VI) adsorption process. FTIR and XPS verfied the surface coordination of U(VI) via -OH and -COOH groups on LDR acclimated Tradescantia fluminensis surface, and the increasing amounts of the two groups could account for the improved U(VI) adsorption capacity compared to the wild Tradescantia fluminensis. Our present work can indicate that LDR acclimation could be a novel way to obtain biomass adsorbents for U(VI) removal from aqueous solutions.