Ultrathin 2D molybdenum disulfide (MoS2), which is the flagship of 2D transition‐metal dichalcogenide nanomaterials, has drawn much attention in the last few years. 2D MoS2 has been banked as an ...alternative to platinum for highly active hydrogen evolution reaction because of its low cost, high surface‐to‐volume ratio, and abundant active sites. However, when MoS2 is used directly as a photocatalyst, contrary to public expectation, it still performs poorly due to lateral size, high recombination ratio of excitons, and low optical cross section. Besides, simply compositing MoS2 as a cocatalyst with other semiconductors cannot satisfy the practical application, which stimulates the pursual of a comprehensive insight into recent advances in synthesis, properties, and enhanced hydrogen production of MoS2. Therefore, in this Review, emphasis is given to synthetic methods, phase transitions, tunable optical properties, and interfacial engineering of 2D MoS2. Abundant ways of band edge tuning, structural modification, and phase transition are addressed, which can generate the neoteric photocatalytic systems. Finally, the main challenges and opportunities with respect to MoS2 being a cocatalyst and coherent light–matter interaction of MoS2 in photocatalytic systems are proposed.
A potential insight into synthesis methods, phase transitions, and tunable optical properties is reviewed for the rational design of MoS2 photocatalytic systems. Moreover, photocatalytic enhancements of plasmon‐assisted MoS2 are also reviewed to further explore the prospects for MoS2 as a cocatalyst and a photocatalyst.
Mediator is a multiprotein complex that is required for gene transcription by RNA polymerase II. Multiple subunits of the complex show specificity in relaying information from signals and ...transcription factors to the RNA polymerase II machinery, thus enabling control of the expression of specific genes. Recent studies have also provided novel mechanistic insights into the roles of Mediator in epigenetic regulation, transcriptional elongation, termination, mRNA processing, noncoding RNA activation and super enhancer formation. Based on these specific roles in gene regulation, Mediator has emerged as a master coordinator of development and cell lineage determination. Here, we describe the most recent advances in understanding the mechanisms of Mediator function, with an emphasis on its role during development and disease.
The flexibility in structural design of organic semiconductors endows organic solar cells (OSCs) not only great function-tunabilities, but also high potential toward practical application. In this ...work, simple non-fused-ring electron acceptors are developed through two-step synthesis from single aromatic units for constructing efficient OSCs. With the assistance of non-covalent interactions, these rotatable non-fused acceptors (in solution) allow transiting into planar and stackable conformation in condensed solid, promoting acceptors not only feasible solution-processability, but also excellent film characteristics. As results, decent power conversion efficiencies of 10.27% and 13.97% can be achieved in single and tandem OSCs consisting of simple solution-cast blends, in which the fully unfused acceptors exhibit exceptionally low synthetic complexity index. In addition, the unfused acceptor and its based OSCs exhibit promising stabilities under continuous illumination. Overall, this work reveals valuable insights on the structural design of simple and effective electron acceptors with great practical perspectives.
The AB-BA domain wall in gapped graphene bilayers is a rare naked structure hosting topological electronic states. Although it has been extensively studied in theory, a direct imaging of its ...topological edge states is still missing. Here we image the topological edge states at the graphene bilayer domain wall by using scanning tunnelling microscope. The simultaneously obtained atomic-resolution images of the domain wall provide us unprecedented opportunities to measure the spatially varying edge states within it. The one-dimensional conducting channels are observed to be mainly located around the two edges of the domain wall, which is reproduced quite well by our theoretical calculations. Our experiment further demonstrates that the one-dimensional topological states are quite robust even in the presence of high magnetic fields. The result reported here may raise hopes of graphene-based electronics with ultra-low dissipation.
Hybrid perovskite materials are famous for their great application potential in photovoltaics and optoelectronics. Among them, lead‐iodide‐based perovskites receive great attention because of their ...good optical absorption ability and excellent electrical transport properties. Although many believe the ferroelectric photovoltaic effect (FEPV) plays a crucial role for the high conversion efficiency, the ferroelectricity in CH3NH3PbI3 is still under debate, and obtaining ferroelectric lead iodide perovskites is still challenging. In order to avoid the randomness and blindness in the conventional method of searching for perovskite ferroelectrics, a design strategy of fluorine modification is developed. As a demonstration, a nonpolar lead iodide perovskite is modified and a new 2D fluorinated layered hybrid perovskite material of (4,4‐difluorocyclohexylammonium)2PbI4, 1, is obtained, which possesses clear ferroelectricity with controllable spontaneous polarization. The direct bandgap of 2.38 eV with strong photoluminescence also guarantees the direct observation of polarization‐induced FEPV. More importantly, the 2D structure and fluorination are also expected to achieve both good stability and charge transport properties. 1 is not only a 2D fluorinated lead iodide perovskite with confirmed ferroelectricity, but also a great platform for studying the effect of ferroelectricity and FEPV in the context of lead halide perovskite solar cells and other optoelectronic applications.
Through a design strategy of fluorine modification, a nonpolar lead iodide perovskite is modified and a new 2D fluorinated layered hybrid perovskite material of (4,4‐difluorocyclohexylammonium)2PbI4 is obtained, which possesses clear ferroelectricity with controllable spontaneous polarization and ferroelectric photovoltaic effect. The discovery of such a material provides a great platform for the fundamental study of lead halide perovskite solar cells and other optoelectronic applications.
This research focused on the synthesis, characterization, and performance testing of a novel Magnéli phase (TinO2n-1), n = 4 to 6, reactive electrochemical membrane (REM) for water treatment. The ...REMs were synthesized from tubular asymmetric TiO2 ultrafiltration membranes, and optimal reactivity was achieved for REMs composed of high purity Ti4O7. Probe molecules were used to assess outer-sphere charge transfer (Fe(CN)6(4-)) and organic compound oxidation through both direct oxidation (oxalic acid) and formation of OH(•) (coumarin, terephthalic acid). High membrane fluxes (3208 L m(-2) h(-1) bar(-1) (LMH bar(-1))) were achieved and resulted in a convection-enhanced rate constant for Fe(CN)6(4-) oxidation of 1.4 × 10(-4) m s(-1), which is the highest reported in an electrochemical flow-through reactor and approached the kinetic limit. The optimal removal rate for oxalic acid was 401.5 ± 18.1 mmol h(-1) m(-2) at 793 LMH, with approximately 84% current efficiency. Experiments indicate OH(•) were produced only on the Ti4O7 REM and not on less reduced phases (e.g., Ti6O11). REMs were also tested for oxyanion separation. Approximately 67% removal of a 1 mM NO3(-) solution was achieved at 58 LMH, with energy consumption of 0.22 kWh m(-3). These results demonstrate the extreme promise of REMs for water treatment applications.
Objective
Previous research has shown that effective application of angiolytic lasers in microlaryngeal surgery is determined by wavelength, pulse width (PW), and fluence. Recently, a 445‐nm (blue) ...laser (BL) has been developed with a potentially greater hemoglobin absorption than previous lasers. The chick chorioallantoic membrane (CAM) represents a suitable model for testing various settings to find out the most optimal settings of this laser. This study used the CAM model to examine whether successful photoangiolytic effects could be obtained using BL.
Methods
Seven hundred and ninety three third‐order vascular segments of viable CAM were irradiated using BL via 400‐μm diameter fiber, 1 pulse/second, with PW and power varied systematically at standardized fiber‐to‐vessel distances of 1 and 3 mm. Outcome measures including vessel ablation rate (AR), rupture rate (RR), and visible tissue effects were analyzed using Chi‐square test.
Results
Energy levels of 400, 540, and 600 mJ (per pulse) were most effective for vessel ablation. A working distance of 3 mm resulted in higher ablation and less vessel rupture compared with 1 mm at these optimal energy levels. At 3 mm, a longer PW resulted in higher AR. At 1 mm, AR increased with shorter PW and higher power. The 1‐mm working distance resulted in lower tissue effects than 3 mm.
Conclusion
Findings in this study showed that BL was effective in vessel ablation using relevant combination of working distance, PW, and energy levels. To obtain high AR, longer working distance plus longer PW was required and if working distance was reduced, shorter PW should be set.
Level of Evidence
NA Laryngoscope, 131:E1950–E1956, 2021
Multi-criteria decision analysis (MCDA) methods have become increasingly popular in decision-making for sustainable energy because of the multi-dimensionality of the sustainability goal and the ...complexity of socio-economic and biophysical systems. This article reviewed the corresponding methods in different stages of multi-criteria decision-making for sustainable energy, i.e., criteria selection, criteria weighting, evaluation, and final aggregation. The criteria of energy supply systems are summarized from technical, economic, environmental and social aspects. The weighting methods of criteria are classified into three categories: subjective weighting, objective weighting and combination weighting methods. Several methods based on weighted sum, priority setting, outranking, fuzzy set methodology and their combinations are employed for energy decision-making. It is observed that the investment cost locates the first place in all evaluation criteria and CO
2 emission follows closely because of more focuses on environment protection, equal criteria weights are still the most popular weighting method, analytical hierarchy process is the most popular comprehensive MCDA method, and the aggregation methods are helpful to get the rational result in sustainable energy decision-making.
Polymer dielectric capacitors are widely utilized in pulse power devices owing to their high power density. Because of the low dielectric constants of pure polymers, inorganic fillers are needed to ...improve their properties. The size and dielectric properties of fillers will affect the dielectric breakdown of polymer‐based composites. However, the effect of fillers on breakdown strength cannot be completely obtained through experiments alone. In this paper, three of the most important variables affecting the breakdown strength of polymer‐based composites are considered: the filler dielectric constants, filler sizes, and filler contents. High‐throughput stochastic breakdown simulation is performed on 504 groups of data, and the simulation results are used as the machine learning database to obtain the breakdown strength prediction of polymer‐based composites. Combined with the classical dielectric prediction formula, the energy storage density prediction of polymer‐based composites is obtained. The accuracy of the prediction is verified by the directional experiments, including dielectric constant and breakdown strength. This work provides insight into the design and fabrication of polymer‐based composites with high energy density for capacitive energy storage applications.
The effects of single variable and multivariable coupling on the breakdown strength of polymer‐based composites are studied by high‐throughput stochastic breakdown simulation, and a machine learning database is established to obtain breakdown prediction. A universal energy storage density prediction is obtained by combining the breakdown prediction with the classical dielectric formula, and the predictions' accuracy is verified.
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