In recent years, organometal trihalide perovskites have emerged as promising materials for low‐cost, flexible, and highly efficient solar cells. Despite their processing advantages, before the ...technology can be commercialized the poor stability of the organic–inorganic hybrid perovskite materials with regard to humidity, heat, light, and oxygen has be to overcome. Herein, we distill the current state‐of‐the‐art and highlight recent advances in improving the chemical stability of perovskite materials by substitution of the A‐cation and X‐anion. Our hope is to pave the way for the rational design of perovskite materials to realize perovskite solar cells with unprecedented improvement in stability.
Stability rising: The recent advances in improving the chemical stability of perovskite materials in terms of substitution of A‐cation and X‐anion are reviewed. The aim is to open new perspectives for the rational design of perovskite materials to create perovskite solar cells with unprecedented stability for outdoor applications.
Organic-inorganic halide perovskite solar cells have recently attracted much attention due to their low-cost fabrication, flexibility, and high efficiency. The power conversion efficiency achieved ...with such cells was over 22% in 2016 from an initial 3.81% in 2009, highlighting how the cells are now benefiting from the highly optimized morphology of perovskite films. To date, a great number of approaches have been done to improve the morphology of perovskite films, in which additives play an important role in perovskite crystal growth and in the dynamics of the crystallinity, and thus the performance of perovskite solar cells. Herein, we review the recent progress on additives, such as polymers, fullerene, metal halide salts, organic halide salts, inorganic acids, solvents, and nanoparticles, in improving the morphology of perovskite films in terms of the crystal growth, crystallization kinetics, and device performance. We also discuss the importance of further understanding the fundamental homogeneous nucleation process by the use of additives. Further innovation in terms of the additives could help to further develop high-performance devices with long-term stability for future practical applications of perovskite solar cells.
Recent advances in additive engineering for improving the perovskite morphology, charge transport, and excitonic and optical properties have been reviewed.
• Fruit ripening is governed by a complex regulatory network. Reversible histone methylation and demethylation regulate chromatin structure and gene expression. However, little is known about the ...involvement of histone demethylases in regulating fruit ripening.
• Here, we found that the tomato (Solanum lycopersicum) SlJMJ6 encodes a histone lysine demethylase that specifically demethylates H3K27 methylation. Overexpression of SlJMJ6 accelerates tomato fruit ripening, which is associated with the upregulated expression of a large number of ripening-related genes.
• Integrated analysis of RNA-seq and chromatin immunoprecipitation followed by sequencing identified 32 genes directly targeted by SlJMJ6 and transcriptionally upregulated with decreased H3K27m3 in SlJMJ6-overexpressed fruit. Numerous SlJMJ6-regulated genes are involved in transcription regulation, ethylene biosynthesis, cell wall degradation and hormone signaling. Eleven ripening-related genes including RIPENING INHIBITOR (RIN), 1-aminocyclopropane 1-carboxylate synthase-4 (ACS4), 1-aminocyclopropane-1-carboxylate oxidase 1 (ACO1), pectate lyase (PL) and beta-galactosidase 4 (TBG4), and a DNA demethylase DML2, were confirmed to be regulated directly by SlJMJ6 through removing H3K27me3.
• Our results demonstrate that SlJMJ6 is a ripening-prompting H3K27me3 demethylase that activates the expression of the ripening-related genes by modulating H3K27me3, thereby facilitating tomato fruit ripening. Our work also reveals a novel link between histone demethylation and DNA demethylation in regulating fruit ripening. To our knowledge, this is the first report of the involvement of a histone lysine demethylase in the regulation of fruit ripening.
Two-dimensional (2D) semiconductors, in particular transition metal dichalcogenides (TMDCs), have attracted great interest in extending Moore's law beyond silicon
. However, despite extensive efforts
..., the growth of wafer-scale TMDC single crystals on scalable and industry-compatible substrates has not been well demonstrated. Here we demonstrate the epitaxial growth of 2 inch (~50 mm) monolayer molybdenum disulfide (MoS
) single crystals on a C-plane sapphire. We designed the miscut orientation towards the A axis (C/A) of sapphire, which is perpendicular to the standard substrates. Although the change of miscut orientation does not affect the epitaxial relationship, the resulting step edges break the degeneracy of nucleation energy for the antiparallel MoS
domains and lead to more than a 99% unidirectional alignment. A set of microscopies, spectroscopies and electrical measurements consistently showed that the MoS
is single crystalline and has an excellent wafer-scale uniformity. We fabricated field-effect transistors and obtained a mobility of 102.6 cm
V
s
and a saturation current of 450 μA μm
, which are among the highest for monolayer MoS
. A statistical analysis of 160 field-effect transistors over a centimetre scale showed a >94% device yield and a 15% variation in mobility. We further demonstrated the single-crystalline MoSe
on C/A sapphire. Our method offers a general and scalable route to produce TMDC single crystals towards future electronics.
Three-dimensional (3D) hierarchical nanostructures have been demonstrated as one of the most ideal electrode materials in energy storage systems due to the synergistic combination of the advantages ...of both nanostructures and microstructures. In this study, the honeycomb-like mesoporous NiO microspheres as promising cathode materials for supercapacitors have been achieved using a hydrothermal reaction, followed by an annealing process. The electrochemical tests demonstrate the highest specific capacitance of 1250 F g–1 at 1 A g–1. Even at 5 A g–1, a specific capacitance of 945 F g–1 with 88.4% retention after 3500 cycles was obtained. In addition, the 3D porous graphene (reduced graphene oxide, rGO) has been prepared as an anode material for supercapacitors, which displays a good capacitance performance of 302 F g–1 at 1 A g–1. An asymmetric supercapacitor has been successfully fabricated based on the honeycomb-like NiO and rGO. The asymmetric supercapacitor achieves a remarkable performance with a specific capacitance of 74.4 F g–1, an energy density of 23.25 Wh kg–1, and a power density of 9.3 kW kg–1, which is able to light up a light-emitting diode.
It is an urgent problem that the construction solid waste is difficult to be treated, and its recycling provides a way for its treatment. The quality of construction solid waste recycled aggregate is ...lower than that of natural aggregate, which limits its extensive application in building materials. In order to provide a new method for engineering application of recycled aggregate concrete, the influence of vibration mixing on the performances of full replacement recycled aggregate concrete were studied. The performance indexes of recycled aggregate concrete under ordinary mixing and vibration mixing were compared and analyzed. The experimental results show that compared with natural aggregate concrete, the slump of full replacement recycled aggregate concrete decreased by 58.8%, and 7d and 28d compressive strength decreased by 12.9% and 16.1%, and the splitting strength decreased by 30.6% and 20.1%, and the carbonation depth decreased by 91.5%; Compared with natural aggregate concrete using ordinary mixing, the slump of full replacement recycled aggregate concrete using vibration mixing decreased by 50.9%, the 7d and 28d compressive strength decreased by 6.9% and 10.9%, and the splitting strength decreased by 16.9% and 12.4%, and the 28d carbonation depth decreased by 34.9%. The results show that compared with ordinary mixing, vibration mixing can improve the performance of recycled aggregate concrete, which provides a reference for engineering application.
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•A strategy for bonding immiscible Mg/steel by laser-TIG butt fusion welding has proposed.•The AlNi/Mg orientation relationship with the lowest mismatch was 1 0 0AlNi//0 1 1¯ 0Mg, ...(0 1 1¯)AlNi//(2¯ 1 1 0)Mg.•The (1 0 1¯ 2)Mg and (0 1 1)AlNi planes are fully coherent and the interface orientation relations was 1 0 1 0Mg//1 1 1¯AlNi, (1 0 1¯ 2)Mg//(0 1 1)AlNi.
Since Mg/steel fusion welding methods fail in Fe melting point higher than the Mg boiling point, it is difficult to bond immiscible Mg/steel based on butt fusion welding. Here we use four different types of Mg/steel laser-TIG butt fusion welding methods to identify the forming mechanism. One of the key points to control the forming of Mg/steel butt fusion welding is to compensate the burning loss of Mg alloy, and the other is to promote the interfacial reaction. The interface mismatch degree for the higher strength joint has analyzed, and the molecular dynamics simulation results are consistent with the fracture analysis results. The Fe/AlNi interface exhibits a fully coherent relationship. The mismatch degree of the AlNi/Mg interface before the lattice distortion of AlNi and Mg shows the following relationship: (0 1 1¯)AlNi//(2¯ 1 1 0)Mg＜(2 1 1)AlNi//(0 0 0 2)Mg＜(1 1 0)AlNi//(0 0 0 2)Mg＜(2 0 0)AlNi// (0 0 0 2)Mg＜(1 1 0)AlNi//(0 1 1¯1¯)Mg. A most likely orientation relationship for AlNi/Mg is (0 1 1¯)AlNi//(2¯ 1 1 0)Mg and 1 0 0AlNi//0 1 1¯ 0Mg before lattice distortion. The mismatch degree AlNi/Mg interface decreases after lattice distortion. Lattice distortion occurred on the Mg alloy side by HRTEM, and the (1 0 1¯ 2)Mg and (0 1 1)AlNi planes are fully coherent. The Mg/AlNi interface has the following orientation relations: 1 0 1 0Mg//1 1 1¯AlNi, (1 0 1¯ 2)Mg//(0 1 1)AlNi.
•Hydrogen water (HW) treatment significantly delayed pericarp browning of litchi.•HW treatment maintained fruit quality of litchi during postharvest storage.•GSH and secondary metabolites played ...vital role in HW-delaying pericarp browning of litchi.•H2O2 might play a positive role in HW-delaying pericarp browning of litchi.
Litchi fruit were exposed to 0.7 PPM hydrogen water (HW) before storage at 25 ± 1 ℃. HW treatment delayed the pericarp browning and maintained the total soluble solids (TSS) of litchi fruit. Then, a total of 25 antioxidant system-related characters were determined to evaluate the effects of HW on antioxidant system during pericarp browning. Compared with control pericarp, the pericarp of HW-treated litchi fruit exhibited higher levels of superoxide radical (O2−·) scavenging activity, glutathione (GSH), monodehydroascorbate reductase (MDHAR), polyphenol oxidase (PPO) and total flavonoids during whole storage, higher levels of hydrogen peroxide (H2O2), catalase (CAT), glutathione disulfide (GSSG), ascorbate oxidase (AAO) and total phenols only on day 1, and higher levels of ascorbate peroxidase (APX), total anthocyanin, glutathione reductase (GR) and glutathione peroxidases (GPX) at later stage of storage. Those HW-induced antioxidant system-related characters might directly or indirectly enhanced the antioxidant capacity and delayed the pericarp browning of litchi.
Aiming at soft rock ground support issues under conditions of high stress and long-term water immersion, the ground failure mechanism is revealed by taking the deep-water sumps of Jiulong Mine as the ...engineering background and employing field investigation, tests of rock structure, mechanical properties and mineral composition. The main factors leading to the surrounding rock failure include the high and complex stress state of the water sumps, high-clay content and water-weakened rock, and the unreasonable support design. In this paper, the broken and fractured rock mass near roadway opening is considered as ground small-structure, and deep stable rock mass as ground large-structure. A support technology focusing on cutting off the water, strengthening the small structure of the rock and transferring the large structure of the rock is proposed. The proposed support technology of interconnecting the large and small structures, based on high-strength bolts, high-stiffness shotcrete layer plugging water,strengthening the small structure with deep-hole grouting and shallow-hole grouting, highpretensioned cables tensioned twice to make the large and small structures bearing the pressure evenly,channel-steel and high-pretensioned cables are used to control floor heave. The numerical simulation and field test show that this support system can control the rock deformation of the water sumps and provide technical support to similar roadway support designs.
Anthocyanin is part of secondary metabolites, which is induced by environmental stimuli and developmental signals, such as high light and sucrose. Anthocyanin accumulation is activated by the ...MYB-bHLH-WD40 (MBW) protein complex in plants. But the evidence of how plants maintain anthocyanin in response to signals is lacking. Here we perform molecular and genetic evidence to display that HAT1 plays a new breaker of anthocyanin accumulation via post-translational regulations of MBW protein complex. Loss of function of HAT1 in the Arabidopsis seedlings exhibits increased anthocyanin accumulation, whereas overexpression of HAT1 significantly repressed anthocyanin accumulation. We found that HAT1 interacted with MYB75 and thereby interfered with MBW protein complex. Overexpression of HAT1 suppresses abundant anthocyanin phenotype of pap1-D plant. HAT1 is characterized as a transcriptional repressor possessing an N-terminal EAR motif, which determines to interact with TOPLESS corepressor. Repression activity of HAT1 in regulation of gene expression and anthocyanin accumulation can be abolished by deletion or mutation of the EAR motif 1. Chromatin immunoprecipitation assays revealed that MYB75 formed a transcriptional repressor complex with HAT1-TPL by histone H3 deacetylation in target genes. We proposed that HAT1 restrained anthocyanin accumulation by inhibiting the activities of MBW protein complex through blocking the formation of MBW protein complex and recruiting the TPL corepressor to epigenetically modulate the anthocyanin late biosynthetic genes (LBGs).
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
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