Research progress in lead-less or lead-free three-dimensional perovskite absorber materials for solar cells

The trend toward lead-free or lead-less perovskite solar cells(PSCs) has attracted increasing attention over the past few years because the toxicity of lead(Pb) is one of the substantial restrictions for large-scale applications. Researchers have investigated the viability of substituting Pb with other elements(group 14 elements, group 2 elements, transition-metal elements, and group 13 and 15 elements) in the three-dimensional(3 D) perovskites by theoretical calculations and experimental explorations. In this paper, recent research progress in Pb-less and Pb-free PSCs on the perovskite compositions, deposition methods, and device structures are summarized and the main problems that hinder the enhancement of device efficiency and stability are discussed in detail. To date, the fully Sn-based PSCs have shown a power conversion efficiency(PCE) of 8.12% and poor device stability. However, lead-less PSCs have shown higher PCE and a better stability. In addition, the introduction of double-perovskite materials also draws researchers' attention. We believe that the engineering of elemental composition, perovskite deposition methods, and interfacial modification are critical for the future development of Pb-less and Pb-free PSCs.

Study of the Hole Wall Soil's Capacity by the Action of the Bearing Device of Rodless Drilling Rig

In order to ensure the bearing device of rodless drilling rig to press stably against the hole wall, it has to analyze the contact between the soil pore wall and the bearing device to study whether the soil pore will shear failure. This paper uses the method to calculate the additional stress of any point in soil mechanics to get the three-dimensional stress state of any point of the soil pore under the support plate, and use the numerical analysis method to calculate the shear stress and its relative intensity. Under the circumstances of maximum torque and maximum pressure, ABAQUS is used to make a finite element analysis of the capacity of the soil pore. The results of numerical analysis and FEA indicate that in the condition of the support plate will not deform; the contact area between the soil pore and the support plate is rectangular; in the force process, the soil under the ends of the support plate have the trend of yield, while it meets the condition of Mohr-Coulomb not to yield generally.

Lung macrophages are involved in lung injury secondary to repetitive diving

This study aimed to establish an animal model of decompression-induced lung injury(DILI)secondary to repetitive diving in mice and explore the role of macrophages in DILI and the protective effects of high-concentration hydrogen(HCH)on DILI.Mice were divided into three groups:control group,DILI group,and HCH group.Mice were exposed to hyperbaric air at 600 k Pa for 60 min once daily for consecutive 3 d and then experienced decompression.In HCH group,mice were administered with HCH(66.7%hydrogen and 33.3%oxygen)for 60 min after each hyperbaric exposure.Pulmonary function tests were done 6 h after decompression;the blood was harvested for cell counting;the lung tissues were harvested for the detection of inflammatory cytokines,hematoxylin and eosin(HE)staining,and immunohistochemistry;western blotting and polymerase chain reaction(PCR)were done for the detection of markers for M1 and M2 macrophages.Our results showed that bubbles formed after decompression and repeated hyperbaric exposures significantly reduced the total lung volume and functional residual volume.Moreover,repetitive diving dramatically increased proinflammatory factors and increased the markers of both M1 and M2 macrophages.HCH inhalation improved lung function to a certain extent,and significantly reduced the pro-inflammatory factors.These effects were related to the reduction of M1 macrophages as well as the increase in M2 macrophages.This study indicates that repetitive diving damages lung function and activates lung macrophages,resulting in lung inflammation.HCH inhalation after each diving may be a promising strategy for the prevention of DILI.