9 research outputs found

    Molecular Encapsulation of Naphthalene Diimide (NDI) Based π-Conjugated Polymers: A Tool for Understanding Photoluminescence.

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    Funder: Royal Society; Id: http://dx.doi.org/10.13039/501100000288Funder: Winton Programme for the Physics of SustainabilityConjugated polymers are an important class of chromophores for optoelectronic devices. Understanding and controlling their excited state properties, in particular, radiative and non-radiative recombination processes are among the greatest challenges that must be overcome. We report the synthesis and characterization of a molecularly encapsulated naphthalene diimide-based polymer, one of the most successfully used motifs, and explore its structural and optical properties. The molecular encapsulation enables a detailed understanding of the effect of interpolymer interactions. We reveal that the non-encapsulated analogue P(NDI-2OD-T) undergoes aggregation enhanced emission; an effect that is suppressed upon encapsulation due to an increasing π-interchain stacking distance. This suggests that decreasing π-stacking distances may be an attractive method to enhance the radiative properties of conjugated polymers in contrast to the current paradigm where it is viewed as a source of optical quenching

    Zero-Shot Remote Sensing Image Dehazing Based on a Re-Degradation Haze Imaging Model

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    Image dehazing is crucial for improving the advanced applications on remote sensing (RS) images. However, collecting paired RS images to train the deep neural networks (DNNs) is scarcely available, and the synthetic datasets may suffer from domain-shift issues. In this paper, we propose a zero-shot RS image dehazing method based on a re-degradation haze imaging model, which directly restores the haze-free image from a single hazy image. Based on layer disentanglement, we design a dehazing framework consisting of three joint sub-modules to disentangle the hazy input image into three components: the atmospheric light, the transmission map, and the recovered haze-free image. We then generate a re-degraded hazy image by mixing up the hazy input image and the recovered haze-free image. By the proposed re-degradation haze imaging model, we theoretically demonstrate that the hazy input and the re-degraded hazy image follow a similar haze imaging model. This finding helps us to train the dehazing network in a zero-shot manner. The dehazing network is optimized to generate outputs that satisfy the relationship between the hazy input image and the re-degraded hazy image in the re-degradation haze imaging model. Therefore, given a hazy RS image, the dehazing network directly infers the haze-free image by minimizing a specific loss function. Using uniform hazy datasets, non-uniform hazy datasets, and real-world hazy images, we conducted comprehensive experiments to show that our method outperforms many state-of-the-art (SOTA) methods in processing uniform or slight/moderate non-uniform RS hazy images. In addition, evaluation on a high-level vision task (RS image road extraction) further demonstrates the effectiveness and promising performance of the proposed zero-shot dehazing method

    A preliminary study on the formation conditions and weathering leaching enrichment mechanism of secondary phosphorite in the Xinhua phosphate mining area, Zhijin, Guizhou

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    The Xinhua phosphate mining are alocated in Zhijin County, Guizhou Province, is a famous superlarge low-grade phosphate deposit containing rare earth elements in the southwest of China.The average P2O5 grade of the deposit is 17.22%.The proven phosphorite ore resources are 1.348 billion tons, and the rare earth resources are 3 500 kilotons.In recent years, experts and scholars have found that the fluctuation of Xinhua phosphorite ore grade is closely related to weathering, leaching and enrichment effects.To further clarify the influence of weathering and leaching on the element geochemistry as well as the secondary enrichment of phosphate rock, the author focuses on the Gezhongwu ore block and carries out field observations and descriptions of phosphate rock series.A total of 19 chemical analysis samples were collected using block knocking method and 16 rock ore samples were identified through polarizing microscope.On these basis, identification and comprehensive research on the samples were conducted.The results show that the contents of P2O5 in the weathered phosphate rock are 8%-18%, higher than that in the primary phosphate rock, while the contents of MgO are 4%-7%, lower than that in the primary phosphate rock.The weathering intensity of phosphate rock is in the weak to mature stage.The formation of Xinhua weathered phosphate rock in Zhijin County is controlled by lithology, geological structure and hydrological conditions.The purpose of this paper is to provide new information for the further study of the influences of the secondary weathering mineralization of the ore deposit on the chemical composition of phosphate rock, to enrich the metallogenic theories of weathering eluvial phosphate mining in China and to provide the oretical guidance for the rational development and utilization of weathering phosphate resources in the mining area

    CUT&tag-seq analysis of heat stress response in broiler liver provides novel insights into the improved thermotolerance by dietary phloretin

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    This work aimed to study the effect of phloretin on antioxidant profiles through nuclear factor erythroid 2–related 2 (Nrf2)-DNA interactions in the liver of heat-stressed broilers by Cleavage Under Targets and Tagmentation combined with high-throughput sequencing (CUT&Tag-seq). One hundred and sixty 22-day-old Arbor Acres broilers were divided into four groups: a normal temperature group (NT: 22.8–23.4 °C and 46–55.8 % humidity) was fed a basal diet and three high temperature groups (China Summer condition: 29.7–31.7 °C and 77.9–94.8 % humidity) were fed the basal diet supplemented with 0 (HT group), 100 mg/kg (LT group) and 200 mg/kg (PT group) phloretin. Liver samples were taken from 42-day-old broilers. High temperature condition increased (P ≤ 0.05) the malondialdehyde (MDA) level, but decreased (P ≤ 0.05) the activities and mRNA expression levels of glutathione peroxidase (GSH-Px), superoxide dismutase (SOD), catalase (CAT), and Nrf2. Dietary 200 mg/kg phloretin decreased (P ≤ 0.05) the MDA level, but increased (P ≤ 0.05) the activities and mRNA expression levels of GSH-Px, SOD, CAT and Nrf2 in the liver of heat-stressed broilers. CUT&Tag-seq showed that 4042 DEPs were up-regulated, while 2322 DEPs were down-regulated in the PT group compared with the HT group. The Nrf2-binding gene of DEPs contained SOD3, CAT, SOD2, and p38 mitogen-activated protein kinase. Most TOP20 significant KEGG pathways were associated with “Environmental Information Processing”. Summary, phloretin could improve oxidative damage by Nrf2 and its downstream DNA-sites including genes and Nrf2-bingding non-coding RNAs in the liver of heat-stressed broilers
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