Monocular vision-based dynamic calibration method for determining the sensitivities of low-frequency tri-axial vibration sensors.

Low-frequency vibrations exist widely in the natural environment and in human activities. Low-frequency tri-axial vibration sensors are enormously applied in the fields of seismic monitoring, building structure health monitoring, aerospace navigating, etc. Their sensitivity calibration accuracy directly determines whether their applications can work reliably. Although the laser interferometry recommended by the International Standardization Organization (ISO) is commonly used to achieve the vibration calibration, it suffers from the shortages of low-frequency range, high cost, low efficiency, and limited applicable environment. In this study, a novel monocular vision-based dynamic calibration method is proposed, which determines the whole sensitivities of tri-axial sensors by the monocular vision method to accurately measure the spatial input excitation. This method improves the calibration performance by eliminating the installation error and enhancing calibration efficiency via decreasing reinstallations. The experimental results compared with the laser interferometry demonstrate that the investigated method can obtain similar calibration accuracy in the range of 0.16-2 Hz with more efficiency. The corresponding maximum relative deviations of X-, Y-, and Z-axial sensitivities were approximately 2.5%, 1.8%, and 0.4%. In addition, the maximum relative standard deviation of the investigated method was only about 0.3% in this range.

Dynamic buckling response of buried X70 steel pipe with bolted flange connection under two-charge explosion loads.

It is of great significance to investigate the dynamic response of pipes under blasting loads for the operation, assessment, and repair of pipes. However, there are few studies available on the dynamic buckling response of pipes under multiple explosion loads. In the present study, pipe-soil coupling 3-D models are established to investigate the dynamic buckling response of X70 steel pipe with bolted flange connection (BFC) under two-charge explosion loads (Charge A lied on the ground surface and Charge B lied in the soil). The main influencing factors are also discussed, including explosion mode, internal pressure, interval time, mass ratio of charges, and diameter-to-thickness ratio (D/t ratio). When Charges A and B were exploded simultaneously, it is found that the non-pressurized X70 pipe produced more significant cross-sectional deformation than in one-point explosion (Charge A or B). Increasing D/t ratio is advantageous for the anti-explosion of the pipe with BFC. Suitable internal pressure can effectively prevent the buckling deformation of the pipe. Compared with the common straight pipe, BFC system can effectively decrease the local buckling deformation and improve the anti-explosion ability of the pipe due to its higher local stiffness and energy absorption.

Managing Excess Lead Iodide with Functionalized Oxo-Graphene Nanosheets for Stable Perovskite Solar Cells.

Stability issues could prevent lead halide perovskite solar cells (PSCs) from commercialization despite it having a comparable power conversion efficiency (PCE) to silicon solar cells. Overcoming drawbacks affecting their long-term stability is gaining incremental importance. Excess lead iodide (PbI2 ) causes perovskite degradation, although it aids in crystal growth and defect passivation. Herein, we synthesized functionalized oxo-graphene nanosheets (Dec-oxoG NSs) to effectively manage the excess PbI2 . Dec-oxoG NSs provide anchoring sites to bind the excess PbI2 and passivate perovskite grain boundaries, thereby reducing charge recombination loss and significantly boosting the extraction of free electrons. The inclusion of Dec-oxoG NSs leads to a PCE of 23.7 % in inverted (p-i-n) PSCs. The devices retain 93.8 % of their initial efficiency after 1,000 hours of tracking at maximum power points under continuous one-sun illumination and exhibit high stability under thermal and ambient conditions.

Dual Passivation of Perovskite and SnO2 for High-Efficiency MAPbI3 Perovskite Solar Cells.

So far, most techniques for modifying perovskite solar cells (PSCs) focus on either the perovskite or electron transport layer (ETL). For the sake of comprehensively improving device performance, a dual-functional method of simultaneously passivating trap defects in both the perovskite and ETL films is proposed that utilizes guidable transfer of Eu3+ in SnO2 to perovskite. Europium ions are distributed throughout the SnO2 film during the formation process of SnO2, and they can diffuse directionally through the SnO2/perovskite interface into the perovskite, while most of the europium ions remain at the interface. Under the synergistic effect of distributed Eu3+ in the SnO2 and aggregated Eu3+ at the interface, the electron mobilities of ETLs are evidently improved. Meanwhile, diffused Eu3+ ions passivate the perovskite to reduce trap densities at the grain boundaries, which can dramatically elevate the open-circuit voltage (V oc) of PSCs. Finally, the mainly PSCs coated on SnO2:Eu3+ ETL achieve a power conversion efficiency of 20.14%. Moreover, an unsealed device degrades by only 13% after exposure to ambient atmosphere for 84 days.

High-Efficiency Perovskite Solar Cells with Imidazolium-Based Ionic Liquid for Surface Passivation and Charge Transport.

Surface defects have been a key constraint for perovskite photovoltaics. Herein, 1,3-dimethyl-3-imidazolium hexafluorophosphate (DMIMPF6 ) ionic liquid (IL) is adopted to passivate the surface of a formamidinium-cesium lead iodide perovskite (Cs0.08 FA0.92 PbI3 ) and also reduce the energy barrier between the perovskite and hole transport layer. Theoretical simulations and experimental results demonstrate that Pb-cluster and Pb-I antisite defects can be effectively passivated by [DMIM]+ bonding with the Pb2+ ion on the perovskite surface, leading to significantly suppressed non-radiative recombination. As a result, the solar cell efficiency was increased to 23.25 % from 21.09 %. Meanwhile, the DMIMPF6 -treated perovskite device demonstrated long-term stability because the hydrophobic DMIMPF6 layer blocked moisture permeation.

In Situ Grain Boundary Modification via Two-Dimensional Nanoplates to Remarkably Improve Stability and Efficiency of Perovskite Solar Cells.

Even though a record efficiency of 23.3% has been achieved in organic-inorganic hybrid perovskite solar cells, their stability remains a critical issue, which greatly depends on the morphology of perovskite absorbers. Herein, we report a practical grain boundary modification to remarkably improve the humidity and thermal stability by gradually growing in situ two-dimensional nanoplates between the grain boundaries of perovskite films using phenylethylammonium iodide (PEAI). The experimental results show that PEAI nanoplates play a critical role in stabilizing perovskite thin films by reducing the moisture sensitivity and suppressing phase transition at the grain boundaries. In addition to the significant improved ambient stability, the grain boundary modification by PEAI can effectively suppress the nonradiative charge recombination at grain boundaries. As a result, the efficiency of perovskite solar cells is up to 20.34% with significant humidity and thermal stability.

Record Efficiency Stable Flexible Perovskite Solar Cell Using Effective Additive Assistant Strategy.

Even though the power conversion efficiency (PCE) of rigid perovskite solar cells is increased to 22.7%, the PCE of flexible perovskite solar cells (F-PSCs) is still lower. Here, a novel dimethyl sulfide (DS) additive is developed to effectively improve the performance of the F-PSCs. Fourier transform infrared spectroscopy reveals that the DS additive reacts with Pb2+ to form a chelated intermediate, which significantly slows down the crystallization rate, leading to large grain size and good crystallinity for the resultant perovskite film. In fact, the trap density of the perovskite film prepared using the DS additive is reduced by an order of magnitude compared to the one without it, demonstrating that the additive effectively retards transformation kinetics during the thin film formation process. As a result, the PCE of the flexible devices increases to 18.40%, with good mechanical tolerance, the highest reported so far for the F-PSCs. Meanwhile, the environmental stability of the F-PSCs significantly enhances by 1.72 times compared to the device without the additive, likely due to the large grain size that suppresses perovskite degradation at grain boundaries. The present strategy will help guide development of high efficiency F-PSCs for practical applications.

Chelate-Pb Intermediate Engineering for High-Efficiency Perovskite Solar Cells.

Crystallization quality and grain size are key factors in fabricating high-performance planar-type perovskite photovoltaics. Herein, we used 1,8-octanedithiol as an effective additive in the [HC(NH2)2]0.95Cs0.05PbI3 (FA0.95Cs0.05PbI3) solution to improve the FA0.95Cs0.05PbI3 film quality via solution processing. 1,8-Octanedithiol would coordinate with lead to form the chelate-Pb compound, leading to smaller Gibbs free energy during the perovskite crystallization process, facilitating formation of high-quality perovskite films with larger grains, smoother surfaces, lower electron trap densities, and longer carrier lifetimes compared to the nonadditive ones. As a result, the champion efficiency for devices with 3% 1,8-octanedithiol-doped FA0.95Cs0.05PbI3 is raised to 19.36% from 18.39% of a device without the additive. The new technique is a promising way to fabricate perovskite photovoltaics with high performance.

Serine prevented high-fat diet-induced oxidative stress by activating AMPK and epigenetically modulating the expression of glutathione synthesis-related genes.

Serine deficiency has been observed in patients with nonalcoholic fatty liver disease (NAFLD). Whether serine supplementation has any beneficial effects on the prevention of NAFLD remains unknown. The present study was conducted to investigate the effects of serine supplementation on hepatic oxidative stress and steatosis and its related mechanisms. Forty male C57BL/6J mice (9week-old) were randomly assigned into four groups (n=10) and fed: i) a low-fat diet; ii) a low-fat diet supplemented with 1% (wt:vol) serine; iii) a high-fat (HF) diet; and iv) a HF diet supplemented with 1% serine, respectively. Palmitic acid (PA)-treated primary hepatocytes separated from adult mice were also used to study the effects of serine on oxidative stress. The results showed that serine supplementation increased glucose tolerance and insulin sensitivity, and protected mice from hepatic lipid accumulation, but did not significantly decreased HF diet-induced weight gain. In addition, serine supplementation protected glutathione (GSH) antioxidant system and prevented hypermethylation in the promoters of glutathione synthesis-related genes, while decreasing reactive oxygen species (ROS) in mice fed a HF diet. Moreover, we found that serine supplementation increased phosphorylation and S-glutathionylation of AMP-activated protein kinase α subunit (AMPKα), and decreased ROS, malondialdehyde and triglyceride contents in PA-treated primary hepatocytes. However, while AMPK activity or GSH synthesis was inhibited, the abovementioned effects of serine on PA-treated primary hepatocytes were not observed. Our results suggest that serine supplementation could prevent HF diet-induced oxidative stress and steatosis by epigenetically modulating the expression of glutathione synthesis-related genes and through AMPK activation.

Impaired function of the intestinal barrier in a novel sub-health rat model.

Sub-health is a state featuring a deterioration in physiological function between health and illness, and the sub-health condition has surfaced as life-threatening in humans. The aim of the present study was to establish a sub-health model in rats, and investigate the function of the intestinal barrier in the sub-health rats and rats following intervention. To establish a sub­health model, the rats were subjected to a high­fat and sugar diet, motion restriction and chronic stress. Their serum glucose and triglyceride levels, immune function and adaptability were then measured. The levels of diamine oxidase and D­lactic acid in the plasma were analyzed as markers of the intestinal permeability. The protein and mRNA expression levels of anti­apoptotic YWHAZ in the colonic tissue was detected using immunohistochemical and reverse transcription­quantitative polymerase chain reaction analyses In the present study, the sub­health rat model was successfully established, and sub­health factors increased the intestinal permeability and reduced the expression of YWHAZ. Providing sub­health rats with normal living conditions did not improve the function of the intestinal barrier. In conclusion, the results of the present study demonstrated that intestinal disorders in the sub­health rat model may result from the damage caused by reduce intestinal barrier function as well as the decreased expression levels of YWHAZ. Additionally, rats in the sub­health condition did not recover following subsequent exposure to normal living conditions, suggesting that certain exercises or medical intervention may be necessary to improve sub-health symptoms.

miR-27b overexpression improves mitochondrial function in a Sirt1-dependent manner

Resveratrol improves mitochondrial function, and recent evidences demonstrate that miRNAs play important roles in certain effects of resveratrol. In the current study, we found that a microRNA, miR-27b, was significantly induced in a dose-dependent way in skeletal muscle and C2C12 myoblast treated with resveratrol. Our results showed that overexpression of miR-27b could mimic the effects of resveratrol on improving mitochondrial function and glucose uptake in skeletal muscle cells. Subsequently, we found that FOXO1 was a potential target of miR-27b, and the effects of resveratrol on mitochondrial function were significantly affected after inhibition of miR-27b. Moreover, the effects of miR-27b on mitochondrial function were lost after inhibition of Sirt1, although miR-27b and FOXO1 expression were not influenced. Taken together, these data suggested that overexpression of miR-27b could benefit mitochondrial function, while the effects of overexpressed miR-27b were Sirt1-dependent

miR-27b overexpression improves mitochondrial function in a Sirt1-dependent manner.

Resveratrol improves mitochondrial function, and recent evidences demonstrate that miRNAs play important roles in certain effects of resveratrol. In the current study, we found that a microRNA, miR-27b, was significantly induced in a dose-dependent way in skeletal muscle and C2C12 myoblast treated with resveratrol. Our results showed that overexpression of miR-27b could mimic the effects of resveratrol on improving mitochondrial function and glucose uptake in skeletal muscle cells. Subsequently, we found that FOXO1 was a potential target of miR-27b, and the effects of resveratrol on mitochondrial function were significantly affected after inhibition of miR-27b. Moreover, the effects of miR-27b on mitochondrial function were lost after inhibition of Sirt1, although miR-27b and FOXO1 expression were not influenced. Taken together, these data suggested that overexpression of miR-27b could benefit mitochondrial function, while the effects of overexpressed miR-27b were Sirt1-dependent.