The American chestnut (<em>Castanea dentata</em>) was once a dominant tree species in the Appalachian Mountains and played a critical role in the ecological system. However, it was nearly eliminated by che...The American chestnut (<em>Castanea dentata</em>) was once a dominant tree species in the Appalachian Mountains and played a critical role in the ecological system. However, it was nearly eliminated by chestnut blight caused by the Ascomycetous fungus <em>Cryphonectria parasitica</em>. Identification of compounds specific to species and backcross hybrids may help further refine disease resistance breeding and testing. Phenolic compounds produced by plants are significant to their defense mechanisms against fungal pathogens. Therefore, an analytical platform has been developed to estimate the total phenolic content in leaf tissues of the American chestnut, Chinese chestnut (<em>Castanea mollissima</em>), and their backcross breeding generations (B<sub>3</sub>F<sub>2</sub> and B<sub>3</sub>F<sub>3</sub>) using the Folin-Ciocalteu reagent assay with UV/Vis spectrophotometry which may be used to predict blight resistance. Adsorption (765 nm) results from leaf tissue extraction in methanol/water (95%:5% v/v) and pH 2, show that the variations among these four tree species are significant (ANOVA p = 2.3 × 10<sup>-7</sup>). The kinetics of phenolic compound solid-liquid extraction was elaborated using Peleg, second order, Elovich, and power law models. In addition, extensive analysis using headspace solid phase microextraction (SPME) gas chromatography and mass spectrometry was conducted to identify volatile organic compounds (VOCs) from the leaf of American chestnut, Chinese chestnut, and their backcross hybrids B<sub>3</sub>F<sub>2</sub> and B<sub>3</sub>F<sub>3</sub>. A total of 67 VOCs were identified among all chestnut types. Many of the metabolites associated with the Chinese chestnut have been reported to have antifungal properties, whereas the native and hybrid American chestnut metabolites have not. Most of the antifungal metabolites showed the strongest efficacy towards the Ascomycota phylum. A partial least squares discriminant analysis (PLS-DA) model (R<sup>2</sup>X = 0.884, R<sup>2</sup>Y = 0.917, Q<sup>2</sup> = 0.584) differentiated chestnut species and hybrids within the first five principal component (PCs).展开更多
动力电池是电动化飞行得以实现的重要组成部分,其技术层次和安全水准对电动垂直起降飞行器(Electric Vertical Take off and Landing aircraft,eVTOL)的商业化推广尤为重要。本文在典型飞行任务下,研究电池性能对eVTOL飞行器的运营性能...动力电池是电动化飞行得以实现的重要组成部分,其技术层次和安全水准对电动垂直起降飞行器(Electric Vertical Take off and Landing aircraft,eVTOL)的商业化推广尤为重要。本文在典型飞行任务下,研究电池性能对eVTOL飞行器的运营性能、适航性能和安全性能的影响。利用开源软件SUAVE(Stanford University Aerospace Vehicle Environment,SUAVE)对复合翼eVTOL进行了整机与动力总成的建模,利用故障树分析(Fault Tree analysis,FTA)方法对动力总成进行了安全性分析。通过仿真,发现在现有电池技术水平下,电池的放电倍率约束是决定电池性能需求的关键限制条件,针对本文设计的eVTOL,372 Wh/kg是满足所有安全约束的最低能量密度,在使用过程中电池容量的衰退是设计者选择电池能量密度的重要参考指标。单独改善电池的可靠性对动力总成可靠性的提升是有限的,但电池性能的衰退将使电池成为动力总成失效的主要因素。通过FTA发现本文搭建的典型动力总成失效率为1.524×10^(-7),接近SC-VTOL-01中单座飞行器的基础级灾难性故障率要求。展开更多
High effect flocculant compound bacteria were screened out with the product bacteria of flocculant in soil. Their system appraising study shows that two were actionomyces and the other was microzyme among the three ba...High effect flocculant compound bacteria were screened out with the product bacteria of flocculant in soil. Their system appraising study shows that two were actionomyces and the other was microzyme among the three bacteria. According to nSrDNA, the three bacteria were marked at a molecule level and the system growth tree was established, ensuring the position of compound bacteria at the molecule level. The purificant which was made of the compound bacteria has spreading value because of its excellent clearing effect for organic and inorganic polluted water.展开更多
文摘The American chestnut (<em>Castanea dentata</em>) was once a dominant tree species in the Appalachian Mountains and played a critical role in the ecological system. However, it was nearly eliminated by chestnut blight caused by the Ascomycetous fungus <em>Cryphonectria parasitica</em>. Identification of compounds specific to species and backcross hybrids may help further refine disease resistance breeding and testing. Phenolic compounds produced by plants are significant to their defense mechanisms against fungal pathogens. Therefore, an analytical platform has been developed to estimate the total phenolic content in leaf tissues of the American chestnut, Chinese chestnut (<em>Castanea mollissima</em>), and their backcross breeding generations (B<sub>3</sub>F<sub>2</sub> and B<sub>3</sub>F<sub>3</sub>) using the Folin-Ciocalteu reagent assay with UV/Vis spectrophotometry which may be used to predict blight resistance. Adsorption (765 nm) results from leaf tissue extraction in methanol/water (95%:5% v/v) and pH 2, show that the variations among these four tree species are significant (ANOVA p = 2.3 × 10<sup>-7</sup>). The kinetics of phenolic compound solid-liquid extraction was elaborated using Peleg, second order, Elovich, and power law models. In addition, extensive analysis using headspace solid phase microextraction (SPME) gas chromatography and mass spectrometry was conducted to identify volatile organic compounds (VOCs) from the leaf of American chestnut, Chinese chestnut, and their backcross hybrids B<sub>3</sub>F<sub>2</sub> and B<sub>3</sub>F<sub>3</sub>. A total of 67 VOCs were identified among all chestnut types. Many of the metabolites associated with the Chinese chestnut have been reported to have antifungal properties, whereas the native and hybrid American chestnut metabolites have not. Most of the antifungal metabolites showed the strongest efficacy towards the Ascomycota phylum. A partial least squares discriminant analysis (PLS-DA) model (R<sup>2</sup>X = 0.884, R<sup>2</sup>Y = 0.917, Q<sup>2</sup> = 0.584) differentiated chestnut species and hybrids within the first five principal component (PCs).
文摘动力电池是电动化飞行得以实现的重要组成部分,其技术层次和安全水准对电动垂直起降飞行器(Electric Vertical Take off and Landing aircraft,eVTOL)的商业化推广尤为重要。本文在典型飞行任务下,研究电池性能对eVTOL飞行器的运营性能、适航性能和安全性能的影响。利用开源软件SUAVE(Stanford University Aerospace Vehicle Environment,SUAVE)对复合翼eVTOL进行了整机与动力总成的建模,利用故障树分析(Fault Tree analysis,FTA)方法对动力总成进行了安全性分析。通过仿真,发现在现有电池技术水平下,电池的放电倍率约束是决定电池性能需求的关键限制条件,针对本文设计的eVTOL,372 Wh/kg是满足所有安全约束的最低能量密度,在使用过程中电池容量的衰退是设计者选择电池能量密度的重要参考指标。单独改善电池的可靠性对动力总成可靠性的提升是有限的,但电池性能的衰退将使电池成为动力总成失效的主要因素。通过FTA发现本文搭建的典型动力总成失效率为1.524×10^(-7),接近SC-VTOL-01中单座飞行器的基础级灾难性故障率要求。
基金the "973" Project of China ( No 2004CB418505) Innovation Foundation of Jilin University ( No419070200045)
文摘High effect flocculant compound bacteria were screened out with the product bacteria of flocculant in soil. Their system appraising study shows that two were actionomyces and the other was microzyme among the three bacteria. According to nSrDNA, the three bacteria were marked at a molecule level and the system growth tree was established, ensuring the position of compound bacteria at the molecule level. The purificant which was made of the compound bacteria has spreading value because of its excellent clearing effect for organic and inorganic polluted water.
