36 research outputs found

    Hydrothermal combustion synthesis and characterization of Sr2CeO4 phosphor powders

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    In this paper, the blue-light-emitting Sr2CeO4 phosphor powders were prepared by hydrothermal combustion reactions and a subsequent sintering process. During the process, the mixed urea and glycine were both used as leavening agent and fuel. The particle crystallization, surface morphology as well as the luminescence intensities of the Sr2CeO4 phosphor powders were effectively improved by adjusting the amount of glycine and post-sintering temperatures. The Sr2CeO4 phosphor exhibited strong crystallization and well-distributed spherical particle after optimization. Moreover, the intense blue-light emission band with the maximum at 468 nm in the range of 400–600 nm was observed as excited with ultraviolet light 277 nm. In particular, after the precursors were heat-treated at 1100 °C, the samples could be well-excited around 350 nm. The excitation bands were ascribed to the charge transfer from O to Ce, and the enlarged excitation range may facilitate its uses in optoelectronic fields.publishe

    Preliminary exploration of herbal tea products based on traditional knowledge and hypotheses concerning herbal tea selection: a case study in Southwest Guizhou, China

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    Background Herbal tea usually refers to “beverage plants that do not belong to the genus Camellia”, and it holds a significant historical legacy as a traditional beverage among specific regions and ethnic groups. In light of this, our research aims to investigate and analyze the traditional knowledge pertaining to herbal tea plants used by local peo- ple in the Qianxinan Buyi and Miao Autonomous Prefecture, Guizhou Province. We also initiated preliminary efforts to create tea products from herbal tea leaves using various processing techniques. Additionally, we attempted to test hypotheses to elucidate how local people select herbal tea plants. Methods Data related to the use of herbal tea plants in this study were collected through semi-structured interviews and participatory observations in four villages in Qianxinan. Quantitative indicators, including the relative frequency of citation (RFC) and the relative importance (RI) value, were calculated, and the availability of plants was also evalu- ated. General linear model was performed to examine the relationship between the frequency of citation and resource availability, as well as the correlation between the relative frequency of citation and the relative impor- tance, to test both the resource availability hypothesis and the versatility hypothesis. Centella asiatica tea was pro- cessed using techniques from green tea, black tea and white tea, with a preliminary sensory evaluation conducted. Results A total of 114 plant species were documented as being used for herbal teas by local residents, represent- ing 60 families and 104 genera. Of these, 61% of herbal tea plants were found growing in the wild, and 11 species were exotic plants. The family with the highest number of species was Asteraceae (20 species). The study identified 33 major medicinal functions of herbal tea, with clearing heat-toxin and diuresis being the most common func- tions. General linear model revealed a strong correlation (correlation coefficient of 0.72, p < 0.001) between the fre- quency of citation and plant availability, as well as a significant correlation (correlation coefficient of 0.63, p < 0.001) between RFC and RI. Under different processing conditions, the characteristics of Centella asiatica tea exhibited varia- tions and were found to be suitable for consumption

    Comparative analyses of Linderniaceae plastomes, with implications for its phylogeny and evolution

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    IntroductionThe recently established Linderniaceae, separated from the traditionally defined Scrophulariaceae, is a taxonomically complicated family. Although previous phylogenetic studies based on a few short DNA markers have made great contributions to the taxonomy of Linderniaceae, limited sampling and low resolution of the phylogenetic tree have failed to resolve controversies between some generic circumscriptions. The plastid genome exhibits a powerful ability to solve phylogenetic relationships ranging from shallow to deep taxonomic levels. To date, no plastid phylogenomic studies have been carried out in Linderniaceae.MethodsIn this study, we newly sequenced 26 plastid genomes of Linderniaceae, including eight genera and 25 species, to explore the phylogenetic relationships and genome evolution of the family through plastid phylogenomic and comparative genomic analyses.ResultsThe plastid genome size of Linderniaceae ranged from 152,386 bp to 154,402 bp, exhibiting a typical quartile structure. All plastomes encoded 114 unique genes, comprising 80 protein-coding genes, 30 tRNA genes, and four rRNA genes. The inverted repeat regions were more conserved compared with the single-copy regions. A total of 1803 microsatellites and 1909 long sequence repeats were identified, and five hypervariable regions (petN-psbM, rps16-trnQ, rpl32-trnL, rpl32, and ycf1) were screened out. Most protein-coding genes were relatively conserved, with only the ycf2 gene found under positive selection in a few species. Phylogenomic analyses confirmed that Linderniaceae was a distinctive lineage and revealed that the presently circumscribed Vandellia and Torenia were non-monophyletic.DiscussionComparative analyses showed the Linderniaceae plastomes were highly conservative in terms of structure, gene order, and gene content. Combining morphological and molecular evidence, we supported the newly established Yamazakia separating from Vandellia and the monotypic Picria as a separate genus. These findings provide further evidence to recognize the phylogenetic relationships among Linderniaceae and new insights into the evolution of the plastid genomes

    Author Correction: Automated design of a convolutional neural network with multi-scale filters for cost-efficient seismic data classification

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    An amendment to this paper has been published and can be accessed via a link at the top of the paper

    GAAF: Searching Activation Functions for Binary Neural Networks through Genetic Algorithm

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    Binary neural networks (BNNs) show promising utilization in cost and power-restricted domains such as edge devices and mobile systems. This is due to its significantly less computation and storage demand, but at the cost of degraded performance. To close the accuracy gap, in this paper we propose to add a complementary activation function (AF) ahead of the sign based binarization, and rely on the genetic algorithm (GA) to automatically search for the ideal AFs. These AFs can help extract extra information from the input data in the forward pass, while allowing improved gradient approximation in the backward pass. Fifteen novel AFs are identified through our GA-based search, while most of them show improved performance (up to 2.54% on ImageNet) when testing on different datasets and network models. Our method offers a novel approach for designing general and application-specific BNN architecture. Our code is available at http://github.com/flying-Yan/GAAF

    Numerical Simulation of the Effects of Grassland Degradation on the Surface Climate in Overgrazing Area of Northwest China

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    The climatic effects of LUCC have been a focus of current researches on global climate change. The objective of this study is to investigate climatic effects of grassland degradation in Northwest China. Based on the stimulation of the conversion from grassland to other land use types during the next 30 years, the potential effects of grassland degradation on regional climate in the overgrazing area of Northwest China from 2010 to 2040 have been explored with Weather Research and Forecasting model (WRF). The analysis results show that grassland will mainly convert into barren land, croplands, and urban land, which accounts for 42%, 48%, and 10% of the total converted grassland area, respectively. The simulation results indicate that the WRF model is appropriate for the simulation of the impact of grassland degradation on climate change. The grassland degradation during the next 30 years will result in the decrease of latent heat flux, which will further lead to the increase of temperature in summer, with an increment of 0.4–1.2°C, and the decrease of temperature in winter, with a decrement of 0.2°C. In addition, grassland degradation will cause the decrease of precipitation in both summer and winter, with a decrement of 4–20 mm
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