Efficient metal halide perovskite light-emitting diodes with significantly improved light extraction on nanophotonic substrates.

Metal halide perovskite has emerged as a promising material for light-emitting diodes. In the past, the performance of devices has been improved mainly by optimizing the active and charge injection layers. However, the large refractive index difference among different materials limits the overall light extraction. Herein, we fabricate efficient methylammonium lead bromide light-emitting diodes on nanophotonic substrates with an optimal device external quantum efficiency of 17.5% which is around twice of the record for the planar device based on this material system. Furthermore, optical modelling shows that a high light extraction efficiency of 73.6% can be achieved as a result of a two-step light extraction process involving nanodome light couplers and nanowire optical antennas on the nanophotonic substrate. These results suggest that utilization of nanophotonic structures can be an effective approach to achieve high performance perovskite light-emitting diodes

Hydrodynamic Analysis of 3-SPS Wave Energy Conversion Device

Wave energy has the advantages of high energy density, renewability, and wide distribution, and has been highly valued by many coastal countries. The wave energy conversion device can convert wave energy into electric energy, which is of great significance for alleviating problems such as energy crisis and greenhouse effect. The traditional wave energy conversion device can only gain the energy along the heave direction, and the kinetic energy of the buoy is not fully utilized. To improve the energy utilization efficiency of the wave energy conversion device, this paper proposed a new type of 3-SPS wave energy conversion device. Based on linear waves and Lagrangian equation, a hydrodynamic model of the device was established. The displacement and velocity of the device float under the action of linear waves were analyzed. The results show that the 3-SPS wave energy conversion device can collect the kinetic energy of the buoy in its heaving, surging and pitching movement at the same time; the kinetic energy of the buoy in the heaving direction is much greater than the kinetic energy in the surging and pitching directions; the buoy can capture kinetic energy in multiple directions of motion, indicating that the 3-SPS wave energy conversion device has a high energy utilization efficiency. This paper provides some useful references for the optimal design of the new wave energy device

Lutein Protects against Methotrexate-Induced and Reactive Oxygen Species-Mediated Apoptotic Cell Injury of IEC-6 Cells

Purpose High-dose chemotherapy using methotrexate (MTX) frequently induces side effects such as mucositis that leads to intestinal damage and diarrhea. Several natural compounds have been demonstrated of their effectiveness in protecting intestinal epithelial cells from these adverse effects. In this paper, we investigated the protection mechanism of lutein against MTX-induced damage in IEC-6 cells originating from the rat jejunum crypt. Methods: The cell viability, induced-apoptosis, reactive oxygen species (ROS) generation, and mitochondrial membrane potential in IEC-6 cells under MTX treatment were examined in the presence or absence of lutein. Expression level of Bcl2, Bad and ROS scavenging enzymes (including SOD, catalase and Prdx1) were detected by quantitative RT-PCR. Results: The cell viability of IEC-6 cells exposed to MTX was decreased in a dose- and time-dependent manner. MTX induces mitochondrial membrane potential loss, ROS generation and caspase 3 activation in IEC-6 cells. The cytotoxicity of MTX was reduced in IEC-6 cells by the 24 h pre-treatment of lutein. We found that pre-treatment of lutein significantly reduces MTX-induced ROS and apoptosis. The expression of SOD was up-regulated by the pre-treatment of lutein in the MTX-treated IEC-6 cells. These results indicated that lutein can protect IEC-6 cells from the chemo-drugs induced damage through increasing ROS scavenging ability. Conclusion: The MTX-induced apoptosis of IEC-6 cells was shown to be repressed by the pre-treatment of lutein, which may represent a promising adjunct to conventional chemotherapy for preventing intestinal damages

Prospects of Searching for Type Ia Supernovae with 2.5-m Wide Field Survey Telescope

Type Ia Supernovae (SNe Ia) are the thermonuclear explosion of a carbon-oxygen white dwarf (WD) and are well-known as a distance indicator. However, it is still unclear how WDs increase their mass near the Chandrasekhar limit and how the thermonuclear runaway happens. The observational clues associated with these open questions, such as the photometric data within hours to days since the explosion, are scarce. Thus, an essential way is to discover SNe Ia at specific epochs with optimal surveys. The 2.5-m Wide Field Survey Telescope (WFST) is an upcoming survey facility deployed in western China. In this paper, we assess the detecability of SNe Ia with mock observations of WFST. Followed by the volumetric rate, we generate a spectral series of SNe Ia based on a data-based model and introduce the line-of-sight extinction to calculate the brightness from the observer. By comparing with the detection limit of WFST, which is affected by the observing conditions, we can count the number of SNe Ia discovered by mock WFST observations. We expect that WFST can find more than $3.0\times10^{4}$ pre-maximum SNe Ia within one-year running. In particular, WFST could discover about 45 bright SNe Ia, 99 early-phase SNe Ia, or $1.1\times10^{4}$ well-observed SNe Ia with the hypothesized Wide, Deep, or Medium mode, respectively, suggesting WFST will be an influential facility in time-domain astronomy.Comment: Accepted by Univers

catena-Poly[[diaqua­cobalt(II)]-μ2-7-oxa­bicyclo­[2.2.1]heptane-2,3-dicarboxyl­ato-κ4 O 2,O 3,O 7:O 2′]

The polymeric title complex, [Co(C8H8O5)(H2O)2]n was synthesized by reaction of cobalt acetate with 7-oxabicyclo­[2,2,1]heptane-2,3-dicarb­oxy­lic anhydride. The CoII ion is six-coordinated in a distorted octa­hedral environment, binding to two water O atoms, to the ether O atom of the bicyclo­heptane unit, to two carboxyl­ate O atoms from two different carboxyl­ate groups of the same anion and to one carboxyl­ate O atom from a symmetry-related anion. The bridging character of the dianion leads to the formation of ribbons along [001]. The ribbons are linked into a layered network parallel to (010) by several O—H⋯O hydrogen-bonding inter­actions involving the coordinating water mol­ecules as donors and the carboxyl­ate O atoms of neighbouring ribbons as acceptors. The crystal under investigation was an inversion twin

AssistGPT: A General Multi-modal Assistant that can Plan, Execute, Inspect, and Learn

Recent research on Large Language Models (LLMs) has led to remarkable advancements in general NLP AI assistants. Some studies have further explored the use of LLMs for planning and invoking models or APIs to address more general multi-modal user queries. Despite this progress, complex visual-based tasks still remain challenging due to the diverse nature of visual tasks. This diversity is reflected in two aspects: 1) Reasoning paths. For many real-life applications, it is hard to accurately decompose a query simply by examining the query itself. Planning based on the specific visual content and the results of each step is usually required. 2) Flexible inputs and intermediate results. Input forms could be flexible for in-the-wild cases, and involves not only a single image or video but a mixture of videos and images, e.g., a user-view image with some reference videos. Besides, a complex reasoning process will also generate diverse multimodal intermediate results, e.g., video narrations, segmented video clips, etc. To address such general cases, we propose a multi-modal AI assistant, AssistGPT, with an interleaved code and language reasoning approach called Plan, Execute, Inspect, and Learn (PEIL) to integrate LLMs with various tools. Specifically, the Planner is capable of using natural language to plan which tool in Executor should do next based on the current reasoning progress. Inspector is an efficient memory manager to assist the Planner to feed proper visual information into a specific tool. Finally, since the entire reasoning process is complex and flexible, a Learner is designed to enable the model to autonomously explore and discover the optimal solution. We conducted experiments on A-OKVQA and NExT-QA benchmarks, achieving state-of-the-art results. Moreover, showcases demonstrate the ability of our system to handle questions far more complex than those found in the benchmarks.Comment: Project page: https://showlab.github.io/assistgpt

Mechanisms of Enhanced Thermal Stability of Polarization in Lead-Free (Bi 1/2Na 1/2) 0.94Ba 0.06TiO 3/ZnO Ceramic Composites

(Bi 1/2Na 1/2)TiO 3-based solid solutions, one of the major systems of lead-free piezoelectric ceramics, exhibit a low thermal depolarization temperature ( T d~100°C). It was reported that by incorporating 30 mol% ZnO particles to form a ceramic composite of (Bi 1/2Na 1/2) 0.94Ba 0.06TiO 3/ZnO, the depolarization process can be shifted up to ~250 °C. In the present work, a variety of advanced transmission electron microscopy techniques, including in situ heating, annular bright-field, high-angle annular dark-field, geometric phase analysis, energy-dispersive spectrum and electron energy-loss spectroscopy, are employed to investigate the underlying mechanisms for the enhanced thermal stability of polarization in the composite. Furthermore, it is found that the abrupt depolarization in (Bi 1/2Na 1/2) 0.94Ba 0.06TiO 3 at T d becomes diffused over a wide temperature window up to the temperature at maximum dielectric constant ( T m) under the combined actions of the incorporation of Zn into the perovskite lattice, the presence of residual stresses, and the pinning effect on micron-sized domains provided by ZnO particles