Ligand-assisted cation-exchange engineering for high-efficiency colloidal Cs1−xFAxPbI3 quantum dot solar cells with reduced phase segregation

The mixed caesium and formamidinium lead triiodide perovskite system (Cs1−xFAxPbI3) in the form of quantum dots (QDs) offers a pathway towards stable perovskite-based photovoltaics and optoelectronics. However, it remains challenging to synthesize such multinary QDs with desirable properties for high-performance QD solar cells (QDSCs). Here we report an effective oleic acid (OA) ligand-assisted cation-exchange strategy that allows controllable synthesis of Cs1−xFAxPbI3 QDs across the whole composition range (x = 0–1), which is inaccessible in large-grain polycrystalline thin films. In an OA-rich environment, the cross-exchange of cations is facilitated, enabling rapid formation of Cs1−xFAxPbI3 QDs with reduced defect density. The hero Cs0.5FA0.5PbI3 QDSC achieves a certified record power conversion efficiency (PCE) of 16.6% with negligible hysteresis. We further demonstrate that the QD devices exhibit substantially enhanced photostability compared with their thin-film counterparts because of suppressed phase segregation, and they retain 94% of the original PCE under continuous 1-sun illumination for 600 h

TAMEP are brain tumor parenchymal cells controlling neoplastic angiogenesis and progression

Aggressive brain tumors like glioblastoma depend on support by their local environment and subsets of tumor parenchymal cells may promote specific phases of disease progression. We investigated the glioblastoma microenvironment with transgenic lineage-tracing models, intravital imaging, single-cell transcriptomics, immunofluorescence analysis as well as histopathology and characterized a previously unacknowledged population of tumor-associated cells with a myeloid-like expression profile (TAMEP) that transiently appeared during glioblastoma growth. TAMEP of mice and humans were identified with specific markers. Notably, TAMEP did not derive from microglia or peripheral monocytes but were generated by a fraction of CNS-resident, SOX2-positive progenitors. Abrogation of this progenitor cell population, by conditional Sox2-knockout, drastically reduced glioblastoma vascularization and size. Hence, TAMEP emerge as a tumor parenchymal component with a strong impact on glioblastoma progression

Climate-Adaptive Design Strategies of Sports Stadia in a Hot Summer and Cold Winter Zone: A Case Study of Nanjing

Urban planning and design, with the objectives of energy efficiency and climate adaptation, is receiving more and more attention as urban energy consumption keeps rising. As technical representatives with large spans and high difficulties, sports stadia have a broad range of energy conservation and emission reduction compared with traditional buildings and have an extremely close relationship with the energy consumption of the building environment and urban microclimate, so it is necessary to study the climate adaptation design strategy of sports stadia. However, climate adaptive design has not given much thought to sports stadia nowadays. And the energy-saving strategies of sports stadia rely mostly on engineering expertise without taking into account the effect of sports stadia layout, shape, and structure on the urban microclimate. This paper investigates the energy-saving and climate-adaptive design techniques of sports stadia in the hot summer and cold winter zone of China using the layout of sports stadia as the research object. Firstly, we construct a climate adaptive design framework of sports stadia of “layout-shape-structure” based on the characteristics of sports stadia. Secondly, combined with typical examples of large-scale sports stadia in hot summers and cold winters, we establish an abstract model of architectural layout, shape, and structure based on climatic environment. In order to provide climate-adaptive design methods for sports stadia in hot summer and cold winter zones, the ventilation of the external and internal spaces of sports stadia is simulated, quantified, and compared using CFD software. The study’s findings suggest that the layout of sports stadia should take into account the direction of the local wind, that the goal of low energy consumption should guide the choice of building form, and that the internal wind and temperature environment should be stabilized during construction. The study’s findings can serve as a guide for comparable designs that aim to construct sports stadia with reduced carbon footprints

An Improved Recognition Approach for Noisy Multispectral Palmprint by Robust L2 Sparse Representation with a Tensor-Based Extreme Learning Machine

For the past decades, recognition technologies of multispectral palmprint have attracted more and more attention due to their abundant spatial and spectral characteristics compared with the single spectral case. Enlightened by this, an innovative robust L2 sparse representation with tensor-based extreme learning machine (RL2SR-TELM) algorithm is put forward by using an adaptive image level fusion strategy to accomplish the multispectral palmprint recognition. Firstly, we construct a robust L2 sparse representation (RL2SR) optimization model to calculate the linear representation coefficients. To suppress the affection caused by noise contamination, we introduce a logistic function into RL2SR model to evaluate the representation residual. Secondly, we propose a novel weighted sparse and collaborative concentration index (WSCCI) to calculate the fusion weight adaptively. Finally, we put forward a TELM approach to carry out the classification task. It can deal with the high dimension data directly and reserve the image spatial information well. Extensive experiments are implemented on the benchmark multispectral palmprint database provided by PolyU. The experiment results validate that our RL2SR-TELM algorithm overmatches a number of state-of-the-art multispectral palmprint recognition algorithms both when the images are noise-free and contaminated by different noises

Research on the Composite Index of the Modern Chinese Energy System

The Chinese government is going to “push ahead the revolution of energy production and consumption, and establish a clean, low-carbon, secure, and efficient energy system”, which points out a direction for the energy industry in the new era. Using the analytic hierarchy process of the system analysis method, we constructed an indicator system of the modern Chinese energy system, and by determining the weighting of each indicator, we obtained the composite index of the modern Chinese energy system, as well as four sub-indexes of clean, low-carbon, secure, and efficient. Then, we investigated policy changes and energy development characteristics of important periods, and performed historical trend analysis. Finally, we forecasted the composite index and four sub-indexes by 2050, and proposed an energy development path and policy suggestions to achieve a modern Chinese energy system as soon as possible

Nitropyrazole based tricyclic nitrogen-rich cation salts: A new class of promising insensitive energetic materials

Nitrogen-rich compound 5,5′-(4-nitro-1H-pyrazole-3,5-diyl)-bis-(4H-1,2,4-triazole-3,4-diamine) (4) and its energetic salts (5–8) were synthesized. Compounds 4–7 posesse satisfactory mechanical sensitivity (IS > 40 J, FS > 360 N). 4 and 5 have the higher decomposition temperatures (4, 318 °C and 5, 304 °C) than TNT (TNT, 295 °C). Compared with TATB (8114 m•s−1), the calculated detonation velocity of 8 (8716 m•s−1) has a certain advantage. Multi-factor analysis shows that these compounds are promising nitrogen-rich energetic materials