Monodispersed MgO microspheres were successfully synthesized by a simple solvothermal method using PEG-400 as solvent. The samples were characterized by X-ray diffraction(XRD) and scanning electron microscopy(SEM). Th...Monodispersed MgO microspheres were successfully synthesized by a simple solvothermal method using PEG-400 as solvent. The samples were characterized by X-ray diffraction(XRD) and scanning electron microscopy(SEM). The results reveal that the precusor was monoclinic Mg5(CO3)4(OH)2·4H2O and composed of nanosheets with the thickness of about 250 nm. By calcining the precusor at 500 °C for 5 min, cubic MgO with similar morphology was obtained. According to the SEM images, it is found that the volume ratio of PEG-400 to deionized water is considered as a crucial factor in the evolution of the morphology. Based on the SEM images obtained under different experimental conditions, a possible growth mechanism which involves self-assembly process was proposed. The thermal decomposition process of MgO precusor was studied by thermogravimetry-differential thermogravimetry(TG-DTG) at different heating rates in air. Thermal analysis kinetics results show that the most probale mechanism models of MgO precusor are An and D3, respectively. In addition, isothermal prediction was studied to quantitatively characterize the thermal decomposition process.展开更多
漆树(Toxicodendron vernicifluum (Stokes) F. A. Barkley)是中国重要的多年生落叶乔木,在生态群落保护和生物制药方面均有较高的利用价值,因此,具有重要的研究意义。本研究首先通过单因素试验确定了漆树SSR-PCR体系,进一步经正交试验...漆树(Toxicodendron vernicifluum (Stokes) F. A. Barkley)是中国重要的多年生落叶乔木,在生态群落保护和生物制药方面均有较高的利用价值,因此,具有重要的研究意义。本研究首先通过单因素试验确定了漆树SSR-PCR体系,进一步经正交试验对其SSR-PCR体系进行优化和筛选。通过PCR扩增筛选出7对条带清晰、多态性好的引物,7对引物最适退火温度分别是:57℃,55.6℃,58℃,57℃,56.8℃,56℃,58℃。基于建立的漆树SSR-PCR体系,利用选出的7对引物,对46个漆树样本进行遗传多样性及遗传结构分析,获得漆树种群内的观察等位基因平均数Na、有效等位基因数Ne、Shannon多样性指数I、Nei's基因多样性指数H分别为1.79、1.24、0.27、0.16,多态位点百分率PPB为88.72%,表明漆树种群内部具有丰富遗传多样性,AMOVA分子方差分析结果显示漆树种群内遗传变异74%高于种群间变异26%,表明种群内的遗传变异大于种群间。导致此种现象可能与漆树的传粉方式、种子特征和种子播撒机制以及环境抑制有一定的关系,本研究结果为合理开发利用漆树天然林,发掘其经济价值提供理论依据。展开更多
基金Project(CL11034)supported by the Training Program of Innovation and Entrepreneurship for Undergraduates of ChinaProject(CSUZC2013033)supported by the Open-End Fund for the Valuable and Precision Instruments of Central South University,ChinaProject(201210533003)supported by National Training Programs of Innovation and Entrepreneurship for Undergraduates,China
文摘Monodispersed MgO microspheres were successfully synthesized by a simple solvothermal method using PEG-400 as solvent. The samples were characterized by X-ray diffraction(XRD) and scanning electron microscopy(SEM). The results reveal that the precusor was monoclinic Mg5(CO3)4(OH)2·4H2O and composed of nanosheets with the thickness of about 250 nm. By calcining the precusor at 500 °C for 5 min, cubic MgO with similar morphology was obtained. According to the SEM images, it is found that the volume ratio of PEG-400 to deionized water is considered as a crucial factor in the evolution of the morphology. Based on the SEM images obtained under different experimental conditions, a possible growth mechanism which involves self-assembly process was proposed. The thermal decomposition process of MgO precusor was studied by thermogravimetry-differential thermogravimetry(TG-DTG) at different heating rates in air. Thermal analysis kinetics results show that the most probale mechanism models of MgO precusor are An and D3, respectively. In addition, isothermal prediction was studied to quantitatively characterize the thermal decomposition process.
文摘漆树(Toxicodendron vernicifluum (Stokes) F. A. Barkley)是中国重要的多年生落叶乔木,在生态群落保护和生物制药方面均有较高的利用价值,因此,具有重要的研究意义。本研究首先通过单因素试验确定了漆树SSR-PCR体系,进一步经正交试验对其SSR-PCR体系进行优化和筛选。通过PCR扩增筛选出7对条带清晰、多态性好的引物,7对引物最适退火温度分别是:57℃,55.6℃,58℃,57℃,56.8℃,56℃,58℃。基于建立的漆树SSR-PCR体系,利用选出的7对引物,对46个漆树样本进行遗传多样性及遗传结构分析,获得漆树种群内的观察等位基因平均数Na、有效等位基因数Ne、Shannon多样性指数I、Nei's基因多样性指数H分别为1.79、1.24、0.27、0.16,多态位点百分率PPB为88.72%,表明漆树种群内部具有丰富遗传多样性,AMOVA分子方差分析结果显示漆树种群内遗传变异74%高于种群间变异26%,表明种群内的遗传变异大于种群间。导致此种现象可能与漆树的传粉方式、种子特征和种子播撒机制以及环境抑制有一定的关系,本研究结果为合理开发利用漆树天然林,发掘其经济价值提供理论依据。
