Pure 2D Perovskite Formation by Interfacial Engineering Yields a High Open-Circuit Voltage beyond 1.28 V for 1.77-eV Wide-Bandgap Perovskite Solar Cells.

Surface post-treatment using ammonium halides effectively reduces large open-circuit voltage (VOC ) losses in bromine-rich wide-bandgap (WBG) perovskite solar cells (PSCs). However, the underlying mechanism still remains unclear and the device efficiency lags largely behind. Here, a facile strategy of precisely tailoring the phase purity of 2D perovskites on top of 3D WBG perovskite and realizing high device efficiency is reported. The transient absorption spectra, cross-sectional confocal photoluminescence mapping, and cross-sectional Kelvin probe force microscopy are combined to demonstrate optimal defect passivation effect and surface electric-field of pure n = 1 2D perovskites formed atop 3D WBG perovskites via low-temperature annealing. As a result, the inverted champion device with 1.77-eV perovskite absorber achieves a high VOC of 1.284 V and a power conversion efficiency (PCE) of 17.72%, delivering the smallest VOC deficit of 0.486 V among WBG PSCs with a bandgap higher than 1.75 eV. This enables one to achieve a four-terminal all-perovskite tandem solar cell with a PCE exceeding 25% by combining with a 1.25-eV low-bandgap PSC.

Study on thermal insulation and seismic effect for fault-crossing tunnel in high geothermal area.

The fault-crossing tunnel in high geothermal areas can be severely damaged under strong earthquake. In this paper, numerical models were established in Flac3d to investigate the thermal insulation and seismic effects under the strong earthquake when using highly damped composite structure. The results showed that the thermal insulation effect of the PC, the PC highly damped composite structure and the SFRC highly damped composite structure were almost the same, which the PC highly damped composite structure was slightly better. After applying the highly damped composite structure, the maximum and minimum principal stresses on the lining decreased, it showed that highly damped composite structure could enhance the seismic effect of tunnel. The safety factor of SFRC highly damped composite structure was 2.420, which was a 28.14% increase compared to PC. Based on numerical simulations, the thermal insulation and seismic effect of SFRC highly damped composite structure was better than other seismic measures. The research can provide a reference for the design of thermal insulation and anti-earthquake for fault-crossing tunnel under strong earthquake in high geothermal area.

Does green credit policy affect corporate debt financing? Evidence from China.

Green finance is one of the most important ways to help companies achieve green transformation and development. We construct a quasi-natural experiment with the "Green Credit Guidelines" and establish a difference-in-differences model to empirically test the implementation effect of the green credit policy in China. The results show that after the implementation of China's green credit policy, the debt financing scale of listed companies in heavily polluting industries has decreased significantly, the debt financing cost has increased significantly, and the debt financing maturity has been shortened significantly, indicating that the green credit policy has inhibited the debt financing of heavily polluting enterprises. We further find that this inhibition has also been affected by the nature of controlling shareholders, environmental information disclosure levels, regional environmental regulations and regional financial development levels. China's green credit policy has played a role in guiding listed companies to go green through the redistribution of debt financing.

Shaking table test on the seismic response of the portal section in soft and hard rock junction.

Tunnel portal sections located in the soft-hard rock junction are vulnerable to the strong earthquake motions in seismically active regions. The main objective of this paper is to investigate the seismic response of tunnel portals located in the soft-hard rock junction. Taking the Baiyunding tunnel in northeast China as a background, a shaking table test with a geometric scaling ratio of 1:30 was built. Details of test setup and procedures are introduced first and then the test results are presented. The discussion of the results is based on the peak ground acceleration (PGA), the longitudinal, the contact stress, and the safety factor. The results show that the soft section of the soft-hard rock junction suffers remarkable damages under strong seismic motions, while the hard rock section is less affected by earthquakes. The increasing soft rock range causes a rise of the forced displacement of tunnel linings, which, together with the seismic inertia force, leads to the increase of the contact stress of the linings, and ultimately resulting in the deterioration of the tunnel seismic safety. To mitigate the seismic damage of tunnel portals in the soft-hard rock junction, rock grouting, bolt support, and other effective reinforced methods should be considered in the seismic design of the soft section.

Engineering application and study on polyurethane-corrugated steel plate insulation lining of existing railway tunnel in seasonal frozen area.

In order to solve the problem of freezing damage treatment and anti-freezing design for railway tunnels in operation in the seasonal frozen area, this paper proposes a polyurethane-corrugated steel plate insulation lining, and studies its thermal insulation effect, relying on a freezing damage treatment project of an existing passenger-dedicated tunnel for on-site application. In this paper, the insulation lining is applied to the actual project and the insulation effect is verified by the field monitoring. The temperature test section was set in the anti-freezing design section. The polyurethane-corrugated steel plate insulation lining proposed in this paper is mainly composed of corrugated steel plate, polyurethane insulation layer and waterproof layer. The polyurethane-corrugated steel insulation lining is applied by using self-made rail flat battery car, door-type scaffolding, arch slide and other construction equipments. The on-site temperature test shows that the insulation effect is obvious. The polyurethane-corrugated steel plate insulation lining has the advantages of fast construction speed, good thermal insulation effect, preventing concrete from peeling off blocks, easy removal and replacement. According to the field temperature test, under the natural temperature outside the tunnel from -18°C to -22°C in winter of 2018-2020, the temperature of the interface between surrounding rock and lining of the tunnel monitoring sections are all above 0°C so that the freezing damage is eliminated from the root. Research results can provide a theoretical basis for the anti-freezing projects of tunnels in seasonal frozen area.

Magnetic Control of Ferrofluid Droplet Adhesion in Shear Flow and on Inclined Surfaces.

The manipulation of ferrofluidic droplets by magnetic fields is a popular technique for controlling fluid transport in open microfluidic systems. We examine the effect of gravity and shear flow external forces on the adhesion properties of sessile ferrofluidic droplets in the presence of a uniform magnetic field. The magnetic field was found to enhance the critical Bond number at which sliding begins on a tilting substrate but suppress the critical Weber number at which sliding begins in a moderate Reynolds number channel flow. The divergent adhesion trends are explained in terms of the shape deformation induced in the ferrofluidic droplet, the substrate wettability, and the apparent contact angle variation induced by the droplet deformation.

Research on large deformation control technology of tunnels in squeezing rock and its application.

Field studies by squeezing rock deformation have shown that large deformation slips can occurs in tunnels in squeezing rock, the tunnels may be partially or completely broken. This article proposed two schemes for controlling the deformation of squeezing rock, which are "resistance combine release" Scheme 1 and "strong support" Scheme 2, the deformation characteristics and deformation mechanism of squeezing rock is researched by Zhongyi Tunnel. The results show that Scheme 2 is superior to Scheme 1 in terms of deformation rate, cumulative deformation, and monthly construction footage. Research results can provide a reference for similar projects.